I was one of the few that played PSO on GCN.  It was bad ass at the time.  I even liked it so much I put up with a monthly subscription to play it online for about a year.  I didn't bother playing the game that much after one of my cousins deleted my lvl 120+ character. 

I had an Xbox, never actually connected it to live, not entirely sure why. I think I was a tech noob back then and was not aware of the plugs that could be used for ethernet connection.. Never actually bothered to find out more about that lol. But this time around I wanted to play Live more often as more of my friends had 360

Got GameCube online and played PSO for a few months. Also played Mario Kart:DD and 1080 Snowboarding online via tunneling on the GC :D.

After that spent about 4 years on Socom 1 / 2 / 3. Made a clan, still played with everyone I met on it today, on FIFA. The best gaming days of my life.

Though I played a lot of Halo 2 on the original Xbox, I didn't play it online until about 2006 when I got the 360. And by then Kameo was the only 360 game I owned, so I 'kind of' played online before joining this generation :P

I played a lot of SOCOM 3 and Metal Gear Online (MGS3)

I'm pretty sure I put a couple hundred hours into MGO. God I miss that game.

original xbox, still the best game console ever.
battlefield 2 modern combat online was probably the best thing ever... always had halo 2 as well.

No I didn't, with the exception of Age of Empires 2 in 2002, I didn't play online until 2005 and Mario Kart DS arrived.

I did a couple times, but of all consoles I only did it on the Dreamcast.

I went online with the Dreamcast but only played Phantasy Star Online. Didn't have the patience for that sort of game back then, didn't play it very much.

The Dreamcast was an amazing console to own and it was a cool feature to have a web browser but not have a PC.

Phantasy Star online (awesome until hackers got to it), Bomberman online (OMG awesome), quake for the Dreamcast
Resident evil outbreak for the PS2, underrated but awesome