We did hardwood floor (oak, toung and groove) in the entire addition we built onto our house several years ago. A 26x26 foot addition took all of a saturday to cut/lay ourselves. Keep in mind that there was really no special cutting (except for the closets) so it went pretty fast. I don't remember how my parent's sanded it, we finished it a room at a time though, so it was probably all done by hand with a power sander. It was nailed down, we rented a nailer locally for under $100 for the weekend. The one we got wasn't pneumatic (good old arm power, you hit a special piston with a hammer).
Hardwood is VERY durable, much more so then lineoleum (it doesn't gouge as easily, and if it does, it's relativly easy to fix). It looks more expensive at first, but when you consider you'll NEVER have to replace it (sand/refinish maybe) unlike lineoleum or carpet which need replaced after a while (better stuff lasts longer, but of course, its more expensive).
We got a KILLER deal on our hardwood floor from a Contractor's Warehouse in Ft. Wayne, Indiana. We live about 70 miles from Ft. Wayne, but it was still worth it to drive there with a truck and pick it up. I don't remember how expensive it was, but I know it was way cheaper then we could have gotten it anywhere else. If you've got one of those near you, it might be worth it to check it out.
Hardwood looks great, I perfer it over carpet in just about every situation. It's a ton easier to keep clean (just an occasional Swiffer-ing) as opposed to carpet and the requied vacuum.