better questions, are: storage capacity, towing capacity, number of adults you want to carry, how long do you want to go out (few hours, day sail, or over night). and of course, BUDGET?
personally, I like the lasers. great boats, good resale, and when you move up you can keep it. also can fit on the roof of most cars. (need 2 adults to lift it off).
sunfish are more popular, but longer, and not quite as fast. but better for 2 than the laser.
a 420 would be the boat for club racing.. which might be the way to go, since you may be able to buy a older boat cheap, and keep it at the club (w/ the others).