What have you played before? oh god, so many games, it's nucking futs. narrow it down a bit. in the last few years i've played farcry, kotor 1 & 2, TES: morrowind and oblivion, half-life 2 ch 1 & 2, lord of the rings online, world of warcraft, lotr battle for middle earth 1 and 2, titan quest, roller coaster tycoon 2 & 3
Farcry, KOTOR, LOTRO, WOW, LOTR: BFME are all quality. I got Titan Quest just recently, and it is AWESOME, if a bit simplistic. Great story, great environs, great graphics, generally a very fun game. Roller Coaster Tycoon - I used to play the first one, never tried the sequels. I loved it, but always got frustrated by the fact that after designing my amazingly awesome roller coasters of death, which I personally would have LOVED to ride on, no one ever came to my parks, and when they did, they complained that the coasters were OTT.
On the negative side, I know Half-Life had a big following, but, having played the whole first game, I just never found it that appealing. yeah, it was ok, but it wasn't brilliant, and doesn't, for me, deserve all the credit it gets. The HL2 engine is awesome though.
Oblivion I rant about regularly. Here it is, copied and pasted for you:
"Freedom sucks. No, seriously, freedom in a game sucks balls. It's what I like to call Oblivion syndrome. Elder Scrolls: Oblivion was so large and so open-ended that I felt no desire or compunction to actually DO anything, I didn't feel drawn into the story, each portal level was a nightmare in terms of carrying all the loot, and the game was too open to be good. The goal of an RPG is to tell a story, while letting you influence the course and outcome of that story, hence making the player feel involved. Mass Effect, KOTOR, Jade Empire and others all fulfil this criterion."
That's just me, though. Some people like having that much choice. me, I prefer the Mass Effect sort of level - lots to do, but not too much, easily accessible, engaging and immediate story. You don't influence the plot very much, which is why KOTOR 1 and 2 are better as RPGs, whereas Mass Effect has the better combat and dialogue system.