Thanks, Mattbu. I don't really have a problem using standard 2x4s for the "bones" of the desk but, rather, with the softness of it. I'm afraid that it won't stand up to the standard bumping and scraping from daily use. Is there a particular 2x4 that I can use which is harder? Similar to the picture, I'm planning on painting everything but the top of the desk, so I don't have to worry about the stain-ability of the studs. Also, any reason why you would consider a thicker top? The only consideration I had for the top of the desk was that it would be a harder, stainable wood that can withstand writing with a ballpoint pen. Finally, is there a problem with doing pocket holes for the top of the wood (other than raw material cost)?
Major tools I have on hand: circular hand saw (battery), compound miter, plunge router (brand new, never used one -- no bits), jigsaw, circular sander, 3 - 12" quick grip clamps, 3 - 6" quick grip clamps, 3 pack chisels
Considering buying for this project -- Harbor Freight Larger clamps (size recs?), pocket hole jig, and kreg rip guide.
Future purchases -- Corded circular saw, more clamps, a few router bits, router table
Future project -- sitting bench w/ shoe storage for master closet