Basically, you're asking for shooters with excellent level design?
I presume you've already played the Half-Life series? If not, definitely play the original + expansions (Blue Shift and Opposing Force). I'm not too keen on the HL2 series, but they're still great games in their own right. I do really hate the Source engine though, for shooters.

As suggested by the other guy, do play Doom 3 and Quake 4. Those games are really solid, especially the former. Don't understand all the hate that it gets. I played a bit of Wolfenstein 2009 as well and it's quite good. That being said, also try RTCW. I enjoyed that game immensely, but admittedly it hadn't aged overly well the last time that I tried it. Obviously you've played Doom 2? That game is so good even today.

Other 'shooters' with possibly some of the best level design ever include the original Deus Ex and now Human Revolution. Both of those are AAAAA (you heard it here first) titles. But you said that you prefer no RPG elements.

Also, FarCry? I recall it being fairly linear, but the large environments provided varying points of access.

Oh and obviously Quake and Quake II. Quake II is an incredible game, nothing else to say. And the first one still gives me the creeps when I play it these days. Can't go wrong with either of these.

Oh and personally, I didn't particularly enjoy Painkiller...

Noooooo... D:

Honestly I prefer the midpoint games about Half-life. The old Shooters really kinda bore me with just getting lost, it's not exploration when I'm back tracking trying to find something I missed. I do think they've gone too far with modern FPS games but the old FPS games always left me with the feeling of: How can anyone use this place, the evil guys have to run around, no den of evil could funtion like this.

Was not sure if I should mention SiN or not, since I'm honestly not sure how many people know about it nowadays. But play it if you haven't already.

http://www.mobygames.com/game/windows/sin
http://www.mobygames.com/game/sin-wages-of-sin

Personally, I found the level design in SiN cryptic. And really didn't think it was a great game, to be honest. But maybe so because it barely ran on my laptop back in the day...

Blake Stone and Wolfenstein 3D were my childhood. My dream game idea I've always had has been to remake Blake Stone.

Sounds like the next kickstarter project to me ...

Thanks for the list of games. Not all of them are quite what I was after but I'll check them out.

I'll definitely be taking a look at DOOM3, Quake 4 etc. I was going to ask about Prey, I really enjoyed the demo and was wondering if the game was worth getting. Does anyone sell it anymore??

Well, this is what wikipedia says:
"Prey was the only major title to utilize the new Triton distribution system, which went out of business mere months after the game's launch. Following the demise of Triton, Prey moved to distribution via Steam."

But I cannot find it on Steam.

Ahh, Blake Stone. Had it not been for Doom coming out like a month later, that game would have become a huge classic, rather than just a cult classic. It had a lot of neat features that didn't show up again in shooters for years afterwards, if ever again. Sad times. Rise of the Triad is fun too, but I always found it a bit... hokey, I guess?

Steam ran out of serial keys, believe it or not.

Yep, like 2 or 3 years ago during a Christmas sale, it went on sale for $5.

I bought it, and maybe 15 minutes later they announced they ran out of keys.

You can find it cheap on Amazon, though.

damn. that brings back some memories...

EA should own the rights to Cybermage too, maybe we'll see it pop up here? ;0