I like immersive games that let you explore their virtual world while you pursue your objective. That means a first person or 3rd person, mostly behind the character, perspective. Crysis gets a lot of things right for me. Love the sandbox environment, being able to pick your battles, approach camps from different angles, choose your playing style. I'm not a rush in and get caught in a firefight type player and Crysis accomodates that by allowing stealth and even the ability to run away from some battles. I like the realism of the game and while game physics and such will no doubt be further developed in future, I think Crytek are on the right track. Generally the options you have feel natural, rather than forced. Need to disable a radar jamming station, well, you can blow it up ... or you can just go up to it, if you manage to get near, and turn it off. Great.
 
Contrast: An early scene in Half-Life 2, Episode 1. You must follow Alyx, who climbs up a wall, out of sight. What is wrong with Gordon Freeman? He can't climb. His jumping is pathetic. Ah, it must be a puzzle for the gravity gun to build a ramp. Stuff like that just bugs the hell out of me. Why are there different rules for the non-playing characters? Perhaps what's wrong here is best illustrated through another Valve game, Portal. It is a game I very much enjoyed, but it is obviously a training course. Not just for the game's character, but for us gamers. Listening to the commentary makes it clear how painstakingly it was designed for that purpose. We have to learn which surfaces allow portals, how to work with energy balls, how to use the cubes, most notoriously the weighted companion cube. I don't particularly want to knock Portal for that, since it is a puzzle game. Like, say, a card game I am happy to learn the rules. It seems to me though that the same mindset that produced Portal pervades game design in general. It's unsurprising really. Until computer power, physics and AI reach another level, gamers must learn about the limitations and idiosynchrasies of the game world, or more precisely the gaming engine. On the other hand there clearly is a push towards ever more realistic games of which the Half-Life series is a part. Except, as you might have guessed by now, Half-Life 2 doesn't really do it for me. I find Crysis' freedom of movement, multiple choices of achieving your goal and lack of artificial puzzles make for a superior game of this, the "realistic" type.
 
OK enough. That preamble leads to the question. What other games do you recommend for me? It doesn't necessarily have to be a shooter. Other comments also welcome.

apart from oblivion, stalker and farcry, i dont think theres much else to be honest.  The witcher?

The Thief games allow you a certain amount of freedom in how you go about your business - although killing everyone generally isn't one of them.  Hitman levels normally have more than one way of completing them too.  Some of the levels in the No-One Lives forever games had some freedom (although some were heavily scripted).
 
Moden games tend to allow this less often, as they concentrate on pretty graphics and a "cinematic" experience.  This is much easier to achieve with scripted "rail" games than a large free-roaming environment.
 
Sounds like what you really want is a decent old-school RPG.  Have you considered the Ultima games?

The Fallout series is pretty open, and if you want, you can destroy everything in a town to steal the goodies. Fallout Tactics even has a "pick your own ending" type deal. It's not quite a Crysis or Farcry though, but I enjoyed the three Fallout games. (Oddly enough Fallout 3 is coming out soon. I wonder why they went 1, 2, Tactics, 3 --- Oh well. )

Try Guild Wars... it doesn't require a monthly subscription.

and is it open??? (i think not, but i may be remembering incorrectly)

The open style of gameplay is something I really miss now that most of the industry is focused on "cinematic feel".  If I wanted to spend 20 mins watching cutscenes, and scripted events on rails, I would have bought a TV.
 
As far as recommendations, I'll go with two older games, Deus Ex, and System Shock.
 

Love these types of games as well OP    
 
It isn't for everyone, but you should check out Boiling Point
 
Definitely check out this summary at least http://www.gamespot.com/pages/foru [...] 766&page=0
 

Is everyone intentionally missing out the Grand Theft Auto series? If you want, then you can wonder around living a perfectly legal life! granted, you'll never be able to EARN money, but if a pedestrian gets hit by a car and you take their money...
Plus, GTA4 is out soon (hopefully the PC port won't be too much later than the consoles)!

Probably the most open ended game I ever played was Morrowind. That was a great game.
 
X2: The Threat and X3: Reunion are open ended space combat flight sim which includes trading and industrial empire building aspects to it. Has a modding community which adds some more content or commands. One such mods add 90 more sectors to explore, trade and fight in. Other mods adds a "crew" to your capital ships (which you can eventually buy if you have enoufgh money) which can improve the ship's stats.

I concur with recommending the X series of games.  Love them
 
You gotta be patient though...

brothers in arms: earned in blood isn't necessarily true sandbox gameplay, but many of the missions can be approached in a variety of ways...plus, the production values behind the Brothers in Arms series are exceedingly high and there is a painstaking attention to detail.
 
If you're looking for multiplayer, the battlefield series has huge maps!  
 
   

 
I always saw oblivion as Lord of the rings meets grand theft auto.  I mean come on the only difference here is i'm going on a towns people/gaurd killing rampage with cold steel instead of an uzi and make my getaway on a horse instead of a car.

I too love open ended games.  Always been a big fan of Zelda, so any games similar I usually love.  Never been a fan of turnbased RPG's, but love action RPG's.  Certain games I think the cinematic linear quality is necessary, i.e. call of duty 4 with the experience they are trying to deliver I think the way the game presents itself is necessary, fast and intense.  If you like military sims, although the controls are slightly clunky, try armed assault(ARMA), you literally can go whereever you want whenever you want the graphics are good, detail is good, mod support wonderful, and I live in the mission editor.  the war takes place on a huge island and you can go wherever you want.  Like I said the only big draw back to this game is the AI is pretty dense, the smoothness of control leaves something to be desired, i.e. you cant move while changing mags, just the movements during animations are not as fluid as most fps games leading to a feeling of restriction in movement.

The fantasy games that have what I would call a near full roaming capability are Oblivion, Gothic 3, Two Worlds, Morrowind + add-ons (forerunner to Oblivion). There is often another advantage in that they have many misc quests, so if you get stuck you can continue with a different quest and come back to that difficult one later.
 
For more modern looking games then Far Cry was the forerunner to Crysis, so if you liked Crysis you'll like Far Cry.
 
For space games you could try the Freelancer, or X3.