I'm a little behind the times, as I don't own any lithium ion tools. With that caveat in mind, my thoughts would be that...

A cordless chainsaw sounds like a dumb idea, but I see that some people find them useful. For the project list you laid out, I don't see any use for one.

I don't know what a 'right angle saw' is, and neither does Google. There are right-angle drills, jig saws and reciprocating saws, but 'right angle saw' turns up zilch.

Don't fall in love with gimmicks, AKA "features." LED guide lights are a gimmick unless you routinely work in the dark.

I prefer smaller, lighter tools, even though I have to change batteries more frequently.

Milwaukee makes excellent quality tools, but they tend towards the heavy and heavy-duty end of the spectrum. Their ergonomics aren't always great.

Makita is solid, dependable stuff.

Ryobi is a lower-end brand, but possibly fine for your purposes.

For my money, I like Bosch. Take a look at whatever they're offering these days.

I have had the blue makita 18v drill/ impact driver set for a little over a year. I had previously used one at work, so I knew what I was getting. I'm more than satisfied. At work we also have the 18v makita skilsaw, which is great.
I got the killer deal of all time on my kit. two drills, two batteries, charger and case for $199 at Home Depot christmas promotion. It is currently on sale for $349. The impact gun with 1 battery is $249 I think.
It's as fine a set as you could hope for in terms of battery life and longevity.
The saw will drain batteries faster than drills.
Casey

Yup, I'd meant a right-angle drill. My bad.

DH re-looked at the Ryobi set from HD last night, and wasn't as impressed as before (once he saw the $199 set included the AutoShift drill, and the light wasn't a LED light). So I will re-look at the Makita and the Bosch, and perhaps the $269 Ryobi set. Not the Milwaukee - when I'd hefted the Milwaukee, it seemed heavy to me too, and Milwaukee was really panned on the 12/2008 "Popular Mechanics" cordless drill review, and even more in the comments.

To sombreuil_mongrel, that sure sounds like a killer deal on the Makita.

Note: to anyone who reads the review I'd linked to, also read the caveat comment #48, listing which tools they thought would be equivalent to each other.

Here is a link that might be useful: Popular Mechanics - Cordless Drill Review

Assembling furniture with any drill-driver is asking for stripped screws and holes.

So far you haven't described any projects that would require a 18 volt or a heavy duty brand. A simple 6 volt cordless Ryobi will do all of what you ask and be just fine. Now, if you're gonna do some home remodeling, build a deck or a fence, or other heavy duty job, then a heavy duty drill will work better for those types of projects.

I just went through the same decision making process, and because we are getting ready for a home remodel/addition, I knew we wanted an 18V. We went with a Rigid, because it felt good in the hand, has a lifetime warranty, and there was a deal with 2 extra batteries and charger for only $100. So far, I like it fine. But for smaller household projects, I still reach for the old Craftsman 9 volt screwdriver. It'd be dreck when assembling a stud wall, but it's fine for all of the tasks you listed.

The Milwaukee 2602 18V Lithium-Ion drill was just rated best by Fine Home Building magazine. I have the larger version and it's one of the best tools I've purchased. It has tons of power and I have not had any problems with the batteries. You may do very well with the little 12V version as it would be great for doing those Ikea cabinets.

I'm not sure you need 18V power for the jobs specified, but for home remodeling jobs where you are drilling through floor joists, etc. 18V is the way to go. You may eventually want both, something small and something heavy duty.

For right angle drills... that depends on how much you want to spend and what you need it for. I have a Dewalt that was over $200. It is VERY heavy duty... runs at 300 and 1200 rpm with over 85 ft-lb of torque. I used it to install over 500 Simpson strong tie 3" SDS screws when I sistered the floor joists with LVLs and it did the job. It's also beeen used to drill countless holes in the joists and studs for wiring. It's big and heavy but a great tool. Again, this is likely overkill for your projects.

Amazon typically has the best prices and it's easy to compare different brands but I like to look at the tools in person too.

Popular Mechanics needs to acquaint itself with Festool:

Here is a link that might be useful: Festool Junkie

I have a wide selection of battery powered tools. The ones that I often reach for first are the Milwaukee Li-ion 12V driver or the 12V impact driver. They have a long battery life, are comfortable, compact in the hand (and fit into small, hard-to-reach spaces), and very powerful. They also have nice quick-change chucks, and a nice range on the clutches. I just used the impact driver to put about 100 2-1/2" lag bolts into my wall and the battery still had plenty of charge left. They're not the right tool for every job, but I use them whenever I can. Other brands that have similar tools and seem to get consistently good reviews are Makita and Panasonic.

I am a homeowner and have owned the Ryobi 18v NiCd set for years and have been pleased with it. It is compatible with the Lithium batteries. It is plenty good enough and well priced.

Ryobi has continued to support the same battery for years so I am able to keep using the same tools and have only bought new batteries once. They offer a like 20+ tools that can use the bettery.

The Radio is handy for $20. The air pump works. The impact driver is awesome for removing screws, or driving them hard without it twisting in your hand. Have the right-hand drill that is good for a few things.

It's kind of fun to collect the tools. Also handy to be able to get it all at HD.

TO make matters confusing Milwaukee makes two different lines of Liion drills and old one and a new one.

http://www.amazon.com/Milwaukee-2601-22-18-Volt-Li-ion-Compact/dp/B000WER5SE

I personally have the above linked item in a 5 or so tool kit and love it 2601 is the drill.

2 things
1) as liveoak said, if you are doing just some ikea cabinets, then you don't need much. but if you are using them for real construction, I would vote for an 18v
2)there are multiple sizes of drills. if you're looking for smaller in size but compact and light go with a "compact" drill. The white Makita set and the Milwaukee compact drill are two good examples of 18v small and light tools.

I love my drill, and as much as I like corded tools for the power when doing a big project, the sawzall and circle saw are great when you just need to cut 1 thing and need portability.

I don't have lithium but do have many of the Ryobi One Plus (One+) series. They can be updated with the lithium ion batteries if desired. There were over 30 different tools I think, I have many/most of them,(27?) some aren't even available in the US/CAN or have been discontinued (Hi-intensity spotlight, brad nailer/stapler, fluorescent lamp, garden sprayer, 6-PACK rolling chest w/miter saw & other tools, etc.)

I actually bought a refurbished starter kit that came with a duffle bag, drill, circular saw, Tuff Sucker vacuum, flashlight, jigsaw, 2 or 3 batteries, charger, etc, and it grew from there. I think the only thing I really bought retail was the weed whacker. Everything else including chainsaws & radio I got on ebay or local ads.

Don't be fooled by the fancy new colors! Just get the blue 18v One+ tools and the lithium batteries & charger! And don't pay retail!

Hope this helps.

P.S. To jon1270:

The cordless chainsaws are great for ice storms that bring down tree limbs that knock out the power, especially if you keep your batteries charged or have the car charger!

Not sure how old your husband is, but the older I get, the more I appreciate my 12v LI cordless drill!

I have the Hitachi and I love it. I also have an 18v Bosch that is much heavier, but also makes both my shoulder and elbow problems flare up much quicker. For fast jobs where I'm not holding the drill above my head or at odd angles, the heavier drill is fine. But, I'd much rather reach for my smaller drill.

So far, I've completely remodeled my house, built a fence, deck, done drywall- all with my 12v drill. I have 3 batteries and when I'm working one is always ready in the charger. The smaller drill has adjustable settings, so I can put together stuff from IKEA without stripping screws. The 18v has way too much power, and would surely strip those. I also have an electric screwdriver that I could use for simpler things, but prefer the feel of the drill.

I think it's a very personal thing, have him try them out buy holding them at the store. And remember, most of the displays don't include the heavy part- the battery- so make sure to take that into consideration. And always buy the best brand you can. The first drill I bought was a Black & Decker, and it has been charged maybe twice in the 6 years I've had it. I prefer quality tools- and that one isn't.