Hi Sean - welcome to the madcap cookers discussion group! On the original Iron Chef one of the commentators used to say, "Bang a gong - we are on" - around here we just run amuck
You've already gotten some good sage advice .... the most important being to figure out what you cook, or want to cook, and buy cookware accordingly. It doesn't take a $100 saucepan to boil a couple of eggs! And, a $250 tri-ply pan isn't going to fry chicken as well as a $25 cast iron skillet from your local Ace Hardware store.
When it comes to Calphalon One - I'm afraid I'm going to rain on your parade.
Calphalon had a great idea that just doesn't seem to work. Traditional cookware (not nonstick) can develope a good fond (those brown bits that stick to the bottom of the pan) that you deglaze and make a gravy/sauce from. Nonstick has never been good at doing that because, well, it's non-stick and the fond can't develope because the proteins and sugars can't carmalize the same way because there is nothing for them to stick onto! The problem with Calphalon One seems to be that the advanced release polymer they infuse the pan with works great for developing a fond - but it's not very nonstick in cooking. To quote from a test done by America's Test Kitchen/Cook's Illustrated .... "This pan's only likeness to a nonstick pan appeared to be in the sink, where it cleaned up as easily as a nonstick if given a brief soak."
If you want to "blacken" or pan fry something (chicken, pork chops, chicken fried steak) or make cornbread - you can't beat cast iron. And, it's hard to beat a cast-iron dutch oven for stews, chili, or pot-roasts.
If you're boiling potatoes, or eggs, or heating up a can of soup - it really doesn't matter. If you're making mac-n-cheese .... a good nonstick would be nice.
What a skillet is can be a matter of nomenclature - something that cookware mfgs. don't always comply with in the true sense - and a lot of us cooks don't follow, either, so it can be confusing when we're all talking about the same thing but calling it different things. A skillet, aka fry pan, has rounded flared sides ... the diameter of the bottom being 1-2 inches smaller than the top. A saute pan, aka chicken fryer or chef's pan, has straight sides and the top and bottom diameter are the same. The saute pan is more likely to come with a lid than a skillet. Now, to bumfuzzel it up more ... a cast iron skillet has basically straight sides that slightly flare out from the diameter of the base.
Some people may poo-poo a 12-qt pasta pot ... but it has other uses, and you really need the capacity if you're going to cook 1-lb of pasta at one time. I have 2,4,6,8,12 qt pots (well, I have a 20-qt aluminum pot I keep under the sink for lots-o-pasta emergencies). They all come in handy for various things. I've got 8,10 inch non-stick omlette pans, 2,4 qt sauciers - hard anodized, anodized nonstick, stainless steel, cast iron ... what I grab just depends on my mood or what I'm cooking.
As for sets vs individual pieces ... sometimes a set isn't a bad idea. If you find a set that contains several pices you want - compare the price of the set to buying each piece you want in the set seperately.
As for baking sheets and such ... if you have a restaurant supply story nearby - go check out their prices for things like baking sheets, cake pans, sheet pans, etc. They are usually better quality and cheaper than the stuff you find at Wal-Mart, Target, etc.
I'm sorry if I used a "scatter-gun" approach to answer your question ... it was kind of a boad question. I would be glad to narrow it down if you have any more questions.