>>/11454/
Underworld

 >>/11453/
The early Rainbow Six games blow the fuck out of the new shit out there. They have a battle planner so well designed you can literally design one and let the AI pass the mission for you. You have to be a complete ADHD faggot not to like this idea.

> Ghost Recon

That series was always shit TBH, go for Operation Flashpoint 1 and its expansions, then play the ARMA games.

> Splinter Cell

All of the Splinter Cell games are good and you'd be a total faggot not to start at the first one.

> MGS3

MGS3 is the best Metal Gear in terms of gameplay to be honest, but story wise MGS1 and MGS2 are god tier and blow it out of the water. MGS3's story is pants on head fucking retarded and marks the point in which Kojima stopped giving a shit as well as his complete loss of respect for the fanbase's intelligence. With that said Metal Gear 2 for the MSX and the PS2 remakes of it play like a Zelda-esque version of MGS1 so if you end up liking MGS1 you can always try playing MG2. And honestly playing MG2 before MGS1 gives a lot of emotional impact towards a certain character who shows up in the game. 

Plus MG2, MGS1, MGS2 and MGS3 all have a certain progression to them. Once you master your skills in one of them, the next one is much easier to play and it lets you have fun looking for easter eggs plus secrets.