For Pc I play Oblivion and Warhammer 40,000's Dawn of war : soulstorm and occasionally WoW with friends.
For Xbox 360 I play COD4 and BF: bad company.
I like Dawn of war's style of RTS. I love how the races are set up and how none are over powered...except Necron

.
I like COD4's style it rewards you and your team for kill streak's with radar, airstrikes, and chopper support. The guns are great, the action is fast paced, and unlike halo leveling up actually means something. You can customize your fighting style through "perks". You get 3 perks blue, red, and green. Blue perks augment your equipment such as more ammo, more grenades, AP mines, C4, RPG, or a bomb detector. Red augment your ability to fight usually through your gun. Red perks include extra gun damage, extra health, increased rate of fire, radar jammer, carry 2 primary weapons, or increased explosive damage. Green perks augment various character attributes such as longer sprinting, steadier hip aim, steadier rifle shots and more breath, better bullet penetration. Green perks can also give you counter attacks such as last stand, when your HP reaches 0 you fall and pull out your pistol for one last attempt to get a kill. There is also martyrdom, drop a live grenade when you're killed. You can also customize your guns with attachments such as, grenade launchers, better sights, long range scopes, MG grips, or silencers.
This game combines my 2 favorite things in online play, leveling and character customization. My favorite class I call gunner, I carry an M60E3 with red dot sight and a golden deagle .50, extra ammo, increased damage, and last stand. My next class I call spec ops. I carry a silenced P90 with a silenced M1911A1 custom. My perks are bomb squad, UAV jammer, and dead silence. this class is literally undetectable unless you physically see me. This class is made to throw my enemies off guard and hunt down snipers. It's near worthless in a fire fight but I can sneak around enemies and knife them from behind or sneak up on heavily dug in opponents.
My class I use in my clan battles however is one I call the invis-a-tube. The invis-a-tube takes an M14 with an M203. My perk 1 is blocked by the GL, my perk 2 is UAV jammer and perk 3 is martyrdom. This class was designed to sneak around and rain death from the flanks. I equip the "noob tube" because it's the streak killer. It takes no skill to kill with and very little time to learn. I equip the M14 so when I run out of grenades I have a high caliber rifle to back me up and I'm a damn good shot with it. Lastly martyrdom is there for a last bit of annoyance and chance to get a kill or 2 while dead. Over all this class is meant to annoy my opponents and frustrate them hoping to throw off their concentration while my team stays in control. While using this class I notice my opponents try to target me leaving them vulnerable to the rest of my clan.