I LOVE my Saitek P990, but unfortuatly, two of its buttons can't actually be used [one enables rapid fire, the other switches between using the D-pad and analog stick]. Still, 6 face buttons, 4 shoulder buttons, a D-pad and two analog sticks are nothing to sneeze at.
Tried a Steelseries a while back [the one EB/Gamestop is currently pushing], and hated it. D-pad was iffy, the controller was heavy, and it drew more power then my Saitek [I had to re-arrange all my USB devices as a result].