For You sounds very dated (as it is now rather old!), Controversy and 1999 less so but those synths and drum machines which were revolutionary at the time now sound rather flat and basic to modern ears. Parade is a funky but eclectic album which you either get or you don't, as I suppose is Sign which at least a few songs you'll love and then get to appreciate the rest. Lovesexy is kind of timeless, Alphabet Street is incredibly catchy and funky, the rest you may find wierd at first but keep listening, the multi-layered music keeps revealing itself to you. Being the two most nearest the present in your list, Graffiti Bridge and Diamonds & Pearls have a more modern production which is probably easier on the ear to a modern listener. Graffiti Bridge has some great tracks mixed in with some throwaway ones, the inclusion of the other artists may put you off. So I'd start with D&P which has some fantastically catchy tracks and thumping rhythms in a more contemporary R&B/rap feel. If you like Purple Rain and the Brits performance, you may be disappointed that there isn't another completely rock album where Prince thrashes his guitar throughout, though all these albums have their moments when he does. If you're after that rock style rather than funk, try picking up Chaos & Disorder which has a few good raw rock tracks - in amongst some lesser material.