I want to get a new game to play online on my PS2 because Ratchet and Clank isn't cutting it, and I wanna try something new. Any suggestions? I wanna get a shooter that is pretty realistic, and the only ones that I can think of are Battlefield 2 and Socom 3. What game should I get? Feel free to suggest any other games.

Metroid Prime Hunters! :P

Nah, you should go for a bit of a 1player experence.
like "Star Ocean - Till The End Of Time",
"Tales of Legendia",
A "Prince of Persia" game,
or Try a little "Armored Core"

Edit: Armored Core might take care of your trigger finger itch, but if you want Online play, you need to be in japan. (dam them and removing net play from the latest game!)

Dragon Quest 8, Kingdom Hearts I + II, and We <3 Katimari.