If I only had ONE pan

It would be my 6-quart sauté pan from All-Clad. Apart from making an omelet, this pan can do everything. I find myself using it 70% of the time when one or more burners are on and I own ~20 pans (multiple all-clad, some ceramic coated iron, cast iron, copper, and regualr steel). I bought it 7 years ago as an indulgence when I got my annual bonus, and have never regretted the purchase. Honestly, this pan is probably worth $500 based on how I've abused it. This pan has played a vital role in many amazing meals and just keeps getting better. The stainless steel is easy to clean and the micro-fissures in the metal allow for good browning when needed. The aluminum core gets it plenty hot for all but the most demanding cooking techniques. While I do have a "new favorite" which I'll blog about in the future, if I only had one pan, this would be it.