Hmmm......tough call....obviously you want something to match your interior color scheme....but after that its a matter of personal taste. I prefer metallic colors....they have more "depth"....my laser red metallic is a knockout in the sun
Candy colors,flip flop pearls and specialty coatings will cost you a lot of change...but again its your choice and budget.Complete "plain jane" paint jobs arent cheap either.
Good luck