With 7684 hours on record, Garry's Mod is easily my most favourite game, but that's too obvious.
Other than that, there's GTA V, especially with LSPDFR and other mods/scripts to support LSPDFR, making a great game even greater. There's also Rainbow Six Siege, which I didn't play much at first, but really enjoy after I started playing again some weeks ago.
And as a last one, there's Battlefield 1. Love the game, especially with all the weapons that are in it (Gotta love having decent weapon sounds compared to Battlefield Hardline). Only thing I don't really like is the way you unlock weapons and how long that can/will take. Should've kept the old system like in Battlefield 4, 3, etc.
I played Mafia 3 at my mate's house and I loved it to bits. Bought it on my machine and I could barely run it, had a crappy fps of 8-12 once I left the warehouse thingy at the start. Refunded it and bought Fallout 4.
World of Warcraft by a mile (@Loejseren@Pear) been playing this game for nearly 12 years now. Pic above is the time on my most played characters, there are an additional ~100 days on other characters as well that I did not include in the pic
Counterstrike Source comes in at a close second, spent thousands of hours in that game as well.
I play lots of games but by far CoD 4 (promod not the shitty default cod) or Medal of Honor Allied Assault (the unique mechanics in that game were hilarious) take it. The clanbase scene for both games was amazing and the communities were fairly small but still most stuff was community-driven and although tournaments were mainly just bragging rights on clanbase since there were not real prizes, it was great fun.
Original CS also comes close, but as time went on servers became more and more cancerous with retarded addons and somehow every time you'd press a fucking key it would send you to a different server.
Hard to say what's my favorite, Most hours spent is on M&B Warband, I can never make my mind up about games.
Mount & Blade: Warband
Counter Strike series
War Thunder (Not Current state)
World of Warships
Naval Action
Rainbow Six Siege
APB (Realtime Worlds / Reloaded)
Arma series
This strategy game is probably my all time favorite. The ammount of time I've spent in this game in one streak is crazy. I Simply love this game and everything it offers.
I've been a huge fan of the battlefield franchise since forever. Battlefield 3 was revolutionary. I've spent over 7000 hours in it and it's just been so got damn fun. Battlefield 4 is of course also a lovely game. That's also a game I have played the sh*t out of and since it came out I've kinda dropped bf3. Both of these were unique and awesome in their own ways.
There are many favorites of mine but there is one game that truly lived up to the hype for me and many others. I am speaking about Portal 2 and it's teaser we received 6 years ago (jesus, that's long ago, I still remember the hype)
I had a blast replaying it with a controller, it's such a great game and yet another sequel that Valve had nailed perfectly. And besides, Wheatley's accent made me love the British accent even more. Here he is in his glory with his gr8 insults:
As for strategy games I really loved playing the heck out of Red Alert 2 (And it's expansion/dlc Yuri's Revenge) along with Generals and Zero Hour. If you want to try the first Red Alert get yourself OpenRA, a modernized version of Red Alert.
I've tried many sandbox games, obviously Garry's Mod being one of them and have put a lot of time in just one server, the result when you had lots of freetime (coming for your record, Bolli hehe xd)
. Kerbal Space Program is also great with it's scenery and campaign mode that has finally been released, been playing it for a good amount of time when I cracked it like a pleb.
JUST LOOK HOW HAPPY HE IS
However, there was one sandbox game that stood out to me in my X360 days, it's this beauty that many people didn't like for some reason but I enjoyed it greatly.
FPS should be obvious. CS 1.6, CZ (+Deleted Scenes), CS:S and maybe CS:GO if they wouldn't have ruined it with useless skins. As for a second and third favorite it would be BF3 and Bad Company 2 along with COD MW 1 and 2 being in the third place of this category, special honorable mention to Team Fortress 2, still sometimes playing it since 2009.