It depends on your budget as well as your preferences.
At the bottom is Pergo or similar. It looks nice and comes in different styles. But it can be scratched or damaged pretty easily.
Next up is vinyl--either square, sheets, or strips. My wife recently redid a couple of rooms (living room, family room) in our house with vinyl strips that look like wood. Better yet, they're textured, so they feel lke wood, too.
You might consider tile, at least in some areas.
Then there's wood--either pre-finished or real. (Sorry, pre-finished is "real" but not in the same way that individual planks of wood, put down, stained, and coated are.)
One thing to keep in mind, though. Lots of building (even condos, for instance) require that something like 75% or 80% of the floor area have carpets or rugs on them. That's for sound control. That remaining 20% generally is taken up with the kitchen, bathroom, and laundry room. So even if you put down a hard surface--any of those described above--you may have to cover that with lots of area rugs.
Hope that helps.