1. Metroid Prime
To me, nothing beats Metroid Prime's exploration and atmosphere. I actually never got a chance to play the original Gamecube version, so the revamped version on the Wii was my first experience with the series. I know many people complained about the original controls, so I was glad I got to play it with the motion controls, which actually work very well. The music is awesome, and there are so many secrets! Those who hate backtracking may dislike parts of this game though.
2. Persona 4
I love the Persona series, and in my opinion, this is the apex. The characters are all so interesting, the English dub is excellent, and the relatively light-hearted nature is a nice contrast with Shin Megami Tensei's typical dark themes.
3. The Witcher 3
This game has a beautiful meld of subsystems, but the CD Projket Red's writing is what brings this to its own tier of RPG. The side quests are so well written and interesting - so much more so than most of the RPG offerings on the market.
4. Donkey Kong Country 2
This game has uber-tight platforming and an addicting soundtrack. I am ashamed to admit I have not played the other two entries in the series, so I need to do that soon. This game had me completely hooked from beginning to start.
5. Halo 3
Halo 3's multiplayer offerings were significant. In particular, the Forge and Custom Games mode made for almost endless replayability. The matchmaking was a significant upgrade from Halo 2, and the single-player campaign did a nice job of wrapping the original trilogy up in an epic way.