8 to 10 hour action-packed thrill rides!

I was going to recommend Spec Ops: The Line, but you already own it :P

You could try the first 2 Max Payne games.

...
You like what I like. Are you my clone?

maybe risk of rain

Brutal Legend

Max Payne 1&2

Alan Wake

Dead Space

Psychonauts (although this one may be a bit longer than 8 hours, but still a very good game)

Edit: Beyond Good & Evil

Enslaved Odyssey to the west (I heard good reviews about that one but didn't play myself)

Call of Juarez: Gunslinger is the game for you. I played a non-steam version (You know what i mean) and it glued my butt to the chair that evening. It has a wacky wild west theme and a good story driven by the whisky fueled memories of an old man. Very fun, check it out

Call of Juarez - Bound in Blood.
Probably my favorite shooter actually, I'm under the impression it's under-rated.
The cover system is fantastic.

No thrill ride as the ones mentioned, but if you're into turn-based games, maybe try out The Banner Saga. 1 playthrough takes about 12-15 hrs and there is absolutely no backtracking of any sorts all your choices are final and impact the story (to some extent)... It's not action packed, rather slow-paced but very story driven, which also seems to be a factor for you. :)

Edit: just going through my library I also found "Dark Messiah of Might & Magic". First Person Action-Adventure with some RPG elements, takes about 10 hrs to complete but warrants multiple playthroughs due to diversity in the combat (ranged, melee, magic, stealth/dagger or combinations of those). It's based on the source engine, so there's some pretty cool physics-based traps to kill those damned orcs :)

Edit 2: another one: "F.E.A.R." series (only played 1 thus far) took me 10 hrs to complete, definite recommendation :)

play Batman games with possible exclusion of Origins one.

if you like platformers, play Deadlight, it's clunky but very moody and has a great story and two endings if you manage to finish Nightmare mode.

Bulletstorm

Alpha Protocol ( kinda RPG but one of the most underrated games of all time )

CoJ Gunslinger

Darkness 2

Crysis 2

Duke Nukem Forever ( so damn bad, I barely finished it but you might like it )

Homefront

Sniper Elite V2

Max Payne 1-2-3

Metro 2033-LL

Although you can stealth it sometimes, wolfenstein: the new order is action packed.

DmC,the new reboot . It's a cool hack 'n' slash game, specialy if you played other Devil May Cry games .
I really enjoyed the fresh new story and style . The combat is fun,specialy if you get that S rank .

Singularity fits your description nicely. It has an interesting story with time travel. The gameplay is an FPS with a bit of bioshock. It has very few moments without shooting stuff. last around 6-8 hours depending on your skill/dificulty level

Is Lost Planet 3 any good? Sounds like my kinda game.

Max Payne 3, Bulletstorm, Singularity, Crysis series, Battlefield 3, Hard Reset, Syndicate.

Pretty much all of the games I would recommend have already been mentioned. One thing that hasn't, however, is a multiplayer game of Borderlands 2. When everyone knows the game, it's brutally fast and action-packed. Plus, when you play with friends, they tend to do weird things, which adds to the entertainment. )

Just make sure that nobody in your group is a "scavenger" or they'll be spending lots of time deciding which loot to keep and which to leave.

You said You prefer 3th person FPS but I'd definitely suggest You Serious Sam games. Mostly killing nd killing, a lot of fun and action... Even those older ones of course (well, maybe even better than the newest). Also, as other people said, Max Payne would be good for You. I haven't played Max Payne 3 yet (unfortunately D: ) but Max Payne 1 and 2 are very nice 3rd person view games.

I'm thinking about one game, not that long, but might be fun to play right away if you just want some action:

Mitsurugi Kamui Hikae, also, on a %75 sale

Metro games are great fun - and pleasing to the eyeballs.

Spec Ops the Line was so incredible, left me devastated.

2 games that haven't been recommended yet:

The Bureau: Xcom Declassified - Was pretty fun, with a decent story, a good way to kill 8-10 hours, not to slow assuming you don't spend forever in the base.

Binary Domain - Basically underrated Mass Effect, but more linear. Pretty good story, super fun. One of my favorite underrated games.

An emotional story that hit fast and hard? Action packed too? Lol, try deadpool :P

Shame is not on steam anymore.

But its more like 5 hours, although you could replay it. After you finish it, the next replay allows you to complete it with all the upgrades.

Noone mentioned Painkiller yet. Why?

Or Serious Sam HDs, as far as I can remember, you can play those in TPP too.

give dishonored an other try.
Also timeshift

Timeshift is indeed great - play on something easy difficulty, use timetravel to ruin everyone's day with guuuns. :D it's entertaining.
Or you can try Hard Reset (FPS) - it's quite like the old FPS names: hidden items behind containers, destructible walls with secrets behind it, and loots of shooting. It's a great game, and you can find it in a bundle too at Bundlestars :)

-Singularity is a great game! Fantastic story, atmosphere, and world and action packed gameplay with some nice mechanics. Also lots of loot. I've heard that it's around 5-7 hrs.

-Warhammer 40k: Space Marine is another great title. Non-stop hack & slash action with both melee and ranged combat. 7-10 hrs. (This is the closet game to your description of a game you wanted) (HIGHLY RECOMMEND)

-Far Cry 3- Blood Dragon is an over-the-top 80's style FPS with great action and a semi-open world 8-12 hrs.

-Shadow Warrior- over-the-top 80's style FPS with fantastic combat and lots of collectables and loot. 6-10 hrs.

-Marlow Briggs and the Mask of Death: Currently $1 and worth every penny. Cheesy 1990's story with hilarious dialogue, acting, and characters. Non-stop God of War style combat. Lots of combos, collectables, and powers. 3-7 hrs.

-POSTAL 2: Ridiculous game that's sexist, racist, and religionist. It has lots of weapons and lots of ridiculous action.