Carlos720 and routsounmanman have good lists.
Ignore a.l.e.x59
Trauma Center is definatly a rent first kind of game. I rented it (the first one) and I loved it, as it is totally new kind of game play experience. I am personally waiting for Trauma Center: New Blood to drop in price, find it used, or if i can find some kind of buy 2 get 1 free deal.
One note about Metroid is that it is not a 1st person shooter in the typical sense of the game. It is much slower and you do a lot of exploring, but it is tough (if you play on veteran, which everyone should start on)
Even though no one will ever suggest it, Mario Party 8 is actually good (my wife actually plays it with me), but nothing spectacular. I'd personally wait to see what Mario Party 9 has to offer before making a decision.
Big Brain Academy is actually very addicting, but not really worth $50 in my opinion, so I'd buy it used. Fun gameplay, and very good multiplayer. Even my little 12 year old sister can beat me if i'm not up to par for the day.








