I think you just said: "anyone who doesn't agree with me, can not be taken seriously.", and then accused others of trolling...  HAHAHA!  VERY progressive thinking!

On topic, Binary if you consider Fallout 3 an FPS (I can see the argument for that); and you haven't played it yet, you really can't go wrong with it, I mean I'm not sure I would classify it as an FPS, but damn if it isn't an excellent, excellent game anyway.

jericho could have been awesome. all the elements were there, but then they just forgot to make it good. it was still a fun play through, and for 20 bucks it's not a bad deal.

For single player FPS experiances you will find a very short list of games recommended because single player FPS experiances are often non existant, or short. The MP is usually the main attraction for most FPS titles. There are a few that I would recommned though.

Bioshock, imo has the best single player FPS experiance. Yes, better then Half Life. But I'm in the minority here. I heard some people recommend the orange box to you, but if your a ps3 only owner, then stay away. It's crap. It's buggy, and the load times are even worse then the 360 version which were more then long enough. It loads and brakes up the action too frequently and for some reason, sometimes even in action packed parts and really throws off the flow of the game. I find this to be a HUGE problem and find it hard to recommend any version really, but the ps3 version is just terrible.
I also heard COD4 thrown about, but it is just too short to recommend as a campeign only title. It took me 6 hours max for my first playthrough.
Resistance has a decent story and length and so I can recommend it but not so much the 2nd if you don't want mp.
Killzone 2 has a decently lengthed and fun single player but look elsewhere for a story. If you can get past the non existant story though it really is one of the best shooters out there. Also, it's worth note that it has bots matches if the main reason you don't want mp is to play with other people who will be better then you, the option is always there to play bots and you can put the ai setting on easy.
Like was said, if you can consider Fallout 3 an FPS, then it is a must. Great length, great story, great everything really.
Borderlands which comes out next month may be worth looking into also as it's an FPS with a heavy rpg element. Think FPS meets Diablo.
Finally, if you are just looking for shooters in general, Uncharted and MGS4 get my highest of recommendations.

BioShock is fantastic. It's pure, condensed awesome. Go buy it now.

Thanks for all the suggestions folks. And I'm actually quite impressed at the relatively low amount of trolling. I'll take some credit for it in the way I framed my OP. And yes I can take a joke and I appreciated the dissolitudes humerous approach. A bit more of that, and people taking it in the spirit it's given would go a long way to toning down the aggro on this site.

The only FPS game I've ever finished was Red Faction. I've played otehrs, including Quake, but never saw them through. So the likelihood of me playing and finishing more than one FPS this gen is pretty low.

I'm inclined towards Bioshock in the first instance, sounds atypical for a FPS which is probably a bonus for someone like me.

For me a decent game length is at least 15 hours preferrably 20+, so for those who are saying KZ2 isn't short at 9 hours I'll have to respectfully disagree, for my own purposes. After Bioshock, if I stilll feel the need for some FPS, I'll probably try (rent) the Orange Box.

I am wondering about MGS4 (to take my own thread off topic for a bit). What with suggestions that PS2 titles are coming to PS3 (via PSN), and the fact I've never played a MGS game should, I hold off on MGS4 until I can play at least one or 2 of the earlier games, or can I get a decent appreciation of MGS4 without having the backstory?

Uncharted 2 is a given.

I have Mirror's Edge, my son bought it. But what I watched of him playing it didn't really grab me (and it didn't really grab him because he hasn't played it much). I'm just not sold on the First Person Platformer concept.

You don't need to play the first few MG's to enjoy MGS4. There is also a data base that you can download for free from the PSN store that can fill you in on the story and charecter bios.

This.

The Orange Box is just awesome (even on PS3).

I'm glad you received some good suggestions.

I never said Killzone 2 was a terrible game, or that he wouldn't be able to find a good FPS to play on the PS3.

I merely said that you are doing yourself a disservice to exclude the Xbox when considering FPS purchases. The mere fact that both Valve and Bungie are Microsoft exclusive speak my opinion in chorus.

^ I'd be doing myself an even bigger disservice in buying a 360 FPS game because it would be a paper weight in my house. And not a very good paper weight at that, since games aren't that heavy, and I live in a windy town.