I use 26W compact bulbs in a reflector hood, but I have used the clamp lights before to start small batches of things, too. Your two lamps should be ok for starting, just remember to keep them very close to your seedlings(a few inches), raising them as the seedlings grow. That said, you won't need the lights until your seeds sprout and you take the plastic cover off of them.
Whether you need a heating mat depends on what seeds you are planting. Peppers germinate better with bottom heat(about 85 degrees), tomatoes can use less and will sprout sooner than peppers. If you've got a lot of different things planted in the one tray, I would just set it somewhere warmish like on the fridge or water heater. What seeds are you starting? You may need to start some separately or at different times.
And, don't forget to read the FAQ's at the top of the forum page for more info.

I'm in the same boat, trying to start small batches of tomato and cucumber next couple of months. I was also going to do clamp lights since I don't need much and don't want to invest in fluorescent light bars. Do regular CFL lights work or do you need some sort of full spectrum bulbs that are special?

Thanks!

What seeds are you starting?
You have a great start for many seeds, but the qty and variety of seeds would help for specific advice.

Let us know

Keriann~

Regular CFL's work fine for starting. If you were growing to maturity inside then you would need more specialized lighting(grow-lights, full spectrum, etc or at least warm and cool). There's a whole other forum for growing under lights, but for starting, CFL's are fine...you just need to give your plants as much light as possible and keep it close so they don't get leggy.
Also keep a small fan blowing 'gently' on your seedlings for a while each day to help prevent damping-off and to sturdy up their stems.

seeds: vegetables: tomato, cucumber, herbs, squash, annuals: zinnia, purple conflower

With those seeds I think you can get away without a heat mat.

Zinnias grow like crazy, I would only start them 2 weeks early as well as your squash. Both don�t benefit form transplanting large plants outside .

Depending on how many of each you are starting, you will probably need more lights (1 or 2 2ft florescent shop lights). If you stick with your two lights your seedlings will not perish, but they may become leggy as the stretch for the light.

Also, your 72 ct. seedling trays will be perfect to start them in or transplant once into, but you will need to transplant them again into larger containers before they are ready for outside because I believe they will get root bound those small trays.

Best of luck and keep us posted!

Keriann~

Your cukes and squash will need warmth and room, so you may want to either start them outside when the soil warms up, or start them in larger pots, say, 3" - 4". It will be easier to transplant them later. What herbs are you starting? Their needs will vary, for instance, Cilantro is a cool weather crop. It will bolt in the heat, so plant it in succession to keep a constant supply and let a few plants go to seed. It can be transplanted out earlier than Basil, which needs warmth and may stunt if planted out too early. I usually treat my Basil like I do my tomatoes.
Purple Coneflower is a perennial and may not flower for you the first season, so find a permanent spot for it..you will be rewarded the second season.
In your zone, you probably won't need to have your plants under lights for too long, so the clamp lights should do, especially if you have the addition of a sunny window(if not, don't start them too early).
Does your starter cell pack separate or is it a solid piece? Some of them separate into 4 or 6 cells and make it easier to transplant when some things grow faster than others.
It will be hit or miss this first time around, just don't get too stressed if you lose stuff and take notes for next year. HTH