I'm shooting for good old 256x256 texture sets. If you want to make textures try to make them a "set" as in they all go together. Right now I'm making a "deserty" set with rusty metal accents and such. Includes some cliffs, sand, and such as well!
You, however, can make your set be whatever you like. We're sticking with a "quasi-realistic" texture feel though. So anything like the TFC sets of old or CS sets of today are good to go.