I would call Prime 2 the worst of the Prime series.

If you are primarily a single player gamer get CoD:WaW. If you are more of a multiplayer type get the Conduit.

Metroid Prime 3 if it counts.

Otherwise, I have to say the target game on Wii Play.

Granted i havent played Echoes in years, but if memory serves correct it was a great game. Bosses were superbly designed and, despite being different from previous Metroid games, felt very much 'Metroid'.

Prime 3, however, hid its biggest flaw in the very progression of the game. Instead of a gigantic overworld, you get smaller, easier sections. I say this as a Metroid enthusiast, Prime 3 was too easy, from the bosses to the actual exploration.

Im gonna say the conduit. The online is great and theres plenty of game types, weapons and maps to keep a player coming back for more. The single player was also good and has some replay value to it.

I think it's The Conduit

Gonna say the conduit even though I don't own it because everyone claims the multiplayer is so bad ass. The multiplayer is always where It's at for a FPS, not some weak six hour single player campaign that can be beaten in a rental. Halo 3 was further proof your FPS needs strong multiplayer to continuously sell well (and Call of Duty as well).

Metroid. They can call it a 'First Person Adventure' but it's still a shooter you use the pointer with, and it's flawless. Has the optional lock on function as well, but you won't need it. Conduit is also flawless in its controls, though a bit shallow.

Well, I haven't played the game, but from what i've seen and heard and read... The Conduit, definitely. If Corruption counts as a FPS, then that. Although it hasn't got any multiplayer.

Quantum of Solace.. .. .. >_>