I'd start with an All-Clad Copper Core stockpot..about $400
A Le Crueset Dutch oven ( 6 qt )...about a friggin fortune LOL
A small All Clad non-stick skillet ..for eggs ONLY..again a f. fortune (It is All clad you know...lol..$$))
I do currently have what I refer to as my "go to" pan..It is a Kitchen Aid Copper Core 12" skillet with a helper handle ..it rocks and is soooo easy to clean..the interior is stailess whick is great for sauteing and searing meats or veggies. You just have to let the items set until a fond is achieved and then flip or move around to brown..gawd I just LOVE this pan..and surprising reasonable..it is an open stock item and costs about $50.00
I have just started my collection..I usually want "everything to match" but realized certain types of pans, in different brands, was the way to go.
I also want an induction burner..boils a stock pot of water in 90 seconds..yep ..90 seconds.
My sister gave me this All-Clad Sauteuse Pan, 4 qt. size, and it totally rocks. It's so versatile...I use it as a big frying /sauteing pan, as a casserole, a dutch oven, soup pot. Definitely the most used pan in my kitchen, and cleans like a dream. Generally they run around $200. If you can only afford one, I'd do this.
I worked in a high end cooking store for years. I can tell you everything you need to know about pots and pans. Like the other posters I love All Clad and Le Creuset. Stainless is always the way to go as long as it has a copper or aluminum core. It's not too heavy, really durable and super easy to clean.
FYI: If it's ever an option for you, get a part time job a cooking store during the Christmas season. Most big stores give up to a 40% discount. Also, all of the major knife and cookware vendors run employee incentives during Christmas, and if you can sell you can clean up. I have at least 6 Le Creuset pieces and 4 All Clads, not to mention a bunch of killer knives (Shun and Wusthof) that were all free!