Sets ususally get you a substantial discount over individual prices. If you can be sure ALL the pieces in the set would be of use to you, it would pay to buy the set. If there are a couple of pieces in a set you wouldn't ever use, you are losing the advantage of any discount.
If you buy SS for your everyday cookware, there are several brands that are reasonably priced. Choosing which pieces to buy would be decided by how and what you cook on a regular basis. Which pots and pan do you use now? That would be a very good indicator of what you should look for.
While All-Clad is among the best, there are other brands that will do the job for a lot less. Calphalon and LeGourmet are two brands that are inexpensive and good stuff. There are others.
Going with SS does not prevent you from getting special pieces for special reasons. LeCruest makes great enameled cast iron dutch ovens. Lodge makes plain cast iron cookware.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan