Strongest I've ever seen: Matrix Aurora.
Best compromise strength to value: Sun CR18
Best looking: Velocity A23 polished.
Most expensive: Velocity A23 polished.
Best value: Alex A.C.E. 19 polished.

I'm sure there are others, these are my experiences.

What I'd buy?
Velocity A23 polished. Hands down: pretty, wide, strong, and light.
The diff between a $30 rim and a $60 rim is zilch once you build and ride the bike, but you'll always have the awesome rims.