Hmmm my personal preferences would be:
Cascade
Fuggles or Willamette
Hallertau or Mt Hood.
Goldings of some sort
These would cover almost all of the beers I would make on a regular basis. Goldings is similar to the fuggles, but they come in to play a lot with Belgians, which I enjoy quite a bit. Hallertau/Mt Hood will cover my hefeweizen addiction. Fuggles/Willamette for the various British beers. Cascades all the way for pale ales. I might change out the goldings for a high AA hop just for more efficient brewing, but probably not.
Fuggles/Willamette & Cascade would be 2 VERY solid choices though I think. Cascades define the American IPA and Fuggles works with a variety of British styles.