Welcome back ! Recommendations will depend on what type of gameplay you prefer(arcade vs sim, run & gun vs tactical realism, etc.). There are a lot of great PC games out there
. Personally, I have the following shooter-type games currently installed: Arma 2(great modern warfare sim), Red Orchestra 1 & 2 (both excellent WWII tactical shooters), Day of Defeat: Source (a more arcady WWII shooter), Deus Ex: Human Revolution (using "give me Deus Ex" difficulty , of course) The witcher(sword-wielding 3rd person RPG with lots of sex & violence), and Orcs Must Die!(a great arcade dungeon defence after-work-stress-reliever). This doesn't include the many excellent flight sims, racing games and strategy games I have installed.