The best looking rims would probably depend on your taste. Like Canuk said, there are thousands upon thousands of rims to choose from and it just depends on the look you're going for. I would probably get 17" lightweight chrome 5 spoke rims if I was going to change mine (sort of like the new '05 TypeS rims).
As far as lowering springs, I don't know too much about the brands, but I would probably not lower my car more than 2". But that's just my preference/opinion.