WarioWare ruined Shooting Gallery in Wii Play for me with Can Shooter. Can Shooter (unlockable game you get after getting to a certain point in single player, which is great to) is the old school light gun game I wanted Shooting Gallery to be. Simple mechanics, excellent controls, and brutally unforgiving difficulty; now that's what I'm talking about.
Don't buy Rayman for multiplayer, it's not designed for that. Single player is fun for a while, but multi's not very good; the sequel scheduled to release later this year is supposed to be much more multiplayer-oriented.
Super Paper Mario is excellent, great mix of platforming and puzzle solving, just make sure you are able to think in three dimensions. I missed RE4 the first time around, but the Wii version is spectacular, and after playing it I don't think I could play it (or a similar game) using an analog stick to aim. RE4 Wii Edition has ruined 3rd-person action games using dual analog for me in the same way Metroid Prime 3 will do a month from now for first-person shooters. I am currently loving Alien Syndrome, but I suppose we should leave discussion of that in its own topic.
If you want a great multiplayer game, wait 3 days and get Mario Strikers, the first proper Wii online game. Also, on the VC, Mario Kart 64 and Bomberman 93 are excellent multiplayer games. And I've had my Wii since launch and every multiplayer outing always comes back to Wii Sports. That thing has incredible lasting power, especially in multiplayer.