Funny, I always thought of it the other way.

Disk on bottom makes sense for things that do not have to be surrounded by heat; such as when making sauces. It ok for the heat to be concentrated just on the bottom.

For searing, pan frying, etc., you want the entire skillet to heat up. So I prefer the fully clad for those items.

There may be technical reasons otherwise, but I feel a lot of this depends on your cooking style. For instance, with skillets I do a lot of shaking and flipping of the pan, rather than stirring with a spoon or spatula. So for me it's especially important that the whole pan be hot. But I stir sauces and the like, so disc-bottoms are fine for pots and saucepans.

I have not had a good experience with pans that have disc bottoms. The rim on the inside of the pan corresponding to where the disc meets the bottom of the sides often burns. The more evenly a pot or pan heats, the happier I am. Go for the fully clad, not the disc-bottom, even on saucepans and stockpots, unless all you use them for is boiling water.

I'm trying to envison what you're saying. None of my disc bottom pans have a rim on the inside. The sidewalls meld smoothly into the bottom. Basically, they are standard one-piece pans to which the disc has been attached.

Nor have I ever had one burn at all, let alone along the line you're describing.

Maybe you're just working at too high a heat?

I thought I was a bit unclear in that description. I will try again. The inside of the pans I tried is smooth, as you describe. However, because the disk on the bottom stops at the edge of the bottom--on the outside of the pan--there is a heat differential between the bottom and the sides. Yes, I do use fairly high heat when I saute, by the way. The pans were purchased at a "big box store." A line of Sitram, if I recall correctly. Oh, and I use a gas range. I gave the pans away.

Curioser and curioser. Sounds like we have similar cooking styles. I cook on gas (hate electric stoves, in fact) too. But even with relatively cheap disc-on cookware (i.e., WearEver) I haven't had that problem.

With stainless it's easy to overheat, particularly if you're used to other types of cookware. Even when sauteeing in the disc-bottom pans I only work at medium heat; whereas I would have worked at high heat in other pans.

Anyway, I don't think there's a right or wrong in this. As I said above, it really boils down (whoops. sorry about that) to your own cooking style and comfort level.

Interesting I find I like the fully clad up the sides for things like soups etc and the disc works fine for saute. My saute pan or a fry pan is never full to touching the sides like sauce pans.

Again, it gets down to cooking style. When I'm sauteeing, I'm shaking, and twisting, and flipping the skillet, and the food touches all parts of it. So I want it evenly heated, and pretty hot all over.

When I'm using pots, on the other hand, the food is usually liquid based. I'm either boiling, or poaching, or stewing in them; or making sauces. Something like that. So all I need is the bottom heat, cuz once the liquid is up to temperature it just has to be maintained.

Thanks for the input. I'm going to try and get fully clad wherever possible (price wise). I did buy one Simply Calphalon with the disc bottom. It is the small no-stick fry pan and I bought it for $14.99 at TJ Maxx. Figured I would give it a try for eggs and such.

From my research, tri ply heats evenly but takes longer to heat up, while disc cookware heats quickly but only on the bottom. Makes sense, since my set is all tri ply except the steamer pot, where quick heating makes better sense than even heating. I have Le Gourmet Chef cookware, which seems to be the closest in design and quality to All Clad at a fraction of the price. I did in fact look at Calphalon but liked LGC better. You can buy online or go to their site and look for a store. My 12-piece set was on sale at the store (in New Jersey) but not online, so definitely research it.

Incidentally, eGullet has a long, quite technical explanation of heat capacity and pot/pan composition. I would trust this gentleman for technical conclusions. I will bop over there to see if I can find the name of the thread. And, despite everything he says, the poster who says "it depends on your cooking style" is right.
Also, I haven't tried the brand myself, but I have heard that some folks find the Henckel's brand that is similar to All-Clad, but with different handles. They look weird, but are reputed to be quite comfortable.

Sorry, it's the Cooking for Engineers forum.
http://www.cookingforengineers.com/article.php?id=120&title=Common+Materials+of+Cookware

Here is a link that might be useful: Cooking for Engineers

The EGullet article is at the link below. More detail than you ever wanted.

Also there is a diagram here of the relative heat conductivity of disk bottom vs straight gauge for reducing:
http://forums.egullet.org/index.php?showtopic=25718&st=207

Here is a link that might be useful: eGullet Stovetop Cookware