Pure creatine monohydrate, but only if you want it. It is cheap though.
Pure whey protein powder is convenient, but not strictly speaking essential.
You could take fish oil. Or you could just eat fish 2-3 times a week or more.
Eat lots of veges, and some fruit. Or if you must, go for some kind of multi++, with some of the goodies found in said foods. Might work...
If you eat a ton of protein in food form, you don't need whey either.
Bulk Nutrients are good, as are a few other companies. Take your pick.