I'm shocked no one has said "Wait until Tuesday/Monday" yet. That's when Metroid Prime 3 comes out, and so far it's looking to be quite good. I seriously think you should take that into consideration. IGN has a
hands-on article up, give it a read. Not much hype seems to be in the game other than certain places on the internet, so I think there won't be many lines. Of course, I don't even have the game yet, so I can't really say whether it will be good or not. But judging by IGN's article, it seems good.
Anyway, Twilight Princess is a good game, too. When compared to other Zelda games, the story-telling is definitely well-done, and they really used Facial Expressions to an advantage. The music in the game isn't exactly great, but they really fit the area you're in most of the time. The only gripe I really have with the game is that it's easy. Really easy. Dungeons will rarely give you a hard time, and I bet you could do the 3-Heart Challenge on your first play-through, and is recommended if you want a challenge. And items suffer the one-dungeon curse, sadly. You'll find a few really cool items that almost never get used throughout the game.
If there's one part of the game that's just plain awesome though, it's the world map. Maybe I'm just easily impressed, but the world map is really cool. It definitely feels more like how Hyrule is normally described this time around. The game has a pretty large amount of stuff to find, like Treasure Chests of money, glowing bugs, and obviously, heart pieces. But don't go in a large field without your horse. Leevers are very, very mean.
However, it's still one of the better games for the Wii, no doubt. If you aren't interested in Prime 3 (Heaaaatheeeen!), then this is probably your next best bet. I don't have Paper Mario, so I can't really speak for it.