Non-shooter game: Demons Souls

Shooter game: Unreal Tournament III

My first invasion was on level 4-1 (I think). I was at the base of a large set of steps and suddenly I was warned that my world was invaded.

I decided to hide between a rock and the steps with my back to a cliff's edge, that way I couldn't be approached from behind. The Black Phantom arrived, charged at me, I rolled out of the way and the stupid fuck went right off the cliff side.

Still, it had my blood really pumping because I didn't want to lose all those souls I had stored up.

Gears of War 2 is the first multiplayer game I got hooked on, the only thing that may pull me away is gears 3. 

I've also had great fun playing tom clancy games but only the coop and not competitive.

Halo Reach: 1900 games at the moment.

Winning Official MGO Tournament August 26th 2010, playing MGO during survival times with my clan. I've spent 2000 hours on MGO in 3 years now.

For me this gen it has been Halo 3. Rocket Race, Assault, Shotty/Snipers (bearing in mind I usually despise snipers) just simply brilliant. The best moment however was in a 'VIP Mode', my side were losing big time but getting into a good position I turned that around with 5 consecutive kills of the opponents VIP who kept going bak to the exact same hiding spot... the fool was asking for it and it isn't like snipers are invisible in Halo a nice obvious trail leads you right to them. This changed the pace of the game and allowed my team to win.

For the original Xbox it was the moment I got into the top 10 on the Star Wars Battlefront 2 leaderboards after borrowing it for two weeks, unfortunately my friend asked for it back and my rise to the top was halted.

Call of Duty 4 on both; not even close.

Lol 1 month later I get all these posts.
Btw mine is GTA 4

Best online experience ever?

Without thinking World of Warcraft. Not a single game does even touch it.
Not playing it anymore though.

Best console online experience? Has to be Resistance 2. The First Shooter game i've ever played in a clan that wasn't only speaking my native language but also consisted of a whole bunch of nice/funny people.

Other remarkable mentions:

Test Drive Unlimited
Halo 2
Resistance: Fall of Man
World of Tanks
Garry's Mod
Minecraft
Modern Warfare 2
Wipeout HD