If you liked Metroid Prime and Metroid Prime 2: Echoes, make sure to get Metroid Prime 3: Corruption. It's a great end to the Metroid Prime trilogy, and the Achievements-like system in the game is great.
I dunno, ... I loved MP and MP2, but MP3 seems just kinda meh in comparison -- the split into many small areas (as opposed to the giant sprawling layouts of the others), and the constant contact with the outside really hurts, I think , and it feels far less immersive than the first two games.
I also find the wii controls
worse than the GC MP controls, mostly because it seems to now put a huge emphasis on precision. I found the GC controls worked really well after you got used to them, but I can never get things working all that well on the wii (maybe that's partly because I have a very small room, and end up usually playing pretty close to the TV, but whatever the reason, it's a less pleasant experience), and MP3 has been pretty frustrating as a result.