Calphalon is niiiiiiiiice. Very heavy, heats evenly, durable, and good finishes so the food doesn't adhere. Probably can't go wrong with anything made by them, I don't think I've ever seen anything that was remotely close to junk. Commercial line is most durable, and you get that nice warranty (not that you'll probably need it). My parents have had several pieces for a long time (15, 20+ years) and the stuff holds up well, even under lots of abuse. The hard annodized finish on the Commercial is great since it's very good about not sticking despite being bare metal and there isn't any plastic coating to baby. The Contemporary and some other lines have a baked-on plastic-y nonstick coating, but it's one of the most durable looking coatings I've seen (something different than the common Teflon junk).
I guess it comes down to whether you want the nonstick coating (Contemporary) or the hard annodized finish (Commercial).
Edit: Other people have mentioned less pricey pans with a thick multilayered bottom and thinner sides, those are good stuff, too. What matters in a pan is thickness of the bottom for even heat and the finish on the cooking surface. I've got some even cheaper pans myself (<40$ since I'm a student and lacking funds) and those work great for now, but they're not nearly as durable and I'll probably want to replace them within 10 years due to wear. If your pans really get used so much that lighter duty stuff wears out within an unacceptable amount of time and you don't want to need to keep buying new ones, the Calphalon or one of the other heavy duty expensive brands might actually be worth their while.