Cricket or Lava are great choices, though some customization to give em a tad more grip MIGHT be desireable, but not necessary.
I prefer the Cricket for size, slimness, and blade-handle proportions and overall usefulness.
Navigator II is nice, touch heavy. Allows a bit more muscle if you need to.
If you can snag one, the Salsa is a great choice too, especially the Ti/ATS-34 version. Pretty rare though.
For a keychain knife... can't beat the Jester or Ladybug though the SPIN belongs in this category IMO, I need something to give it better grip though the two-finger handle does well by itself.