EPTteamliquid - obviously. this is probably the most filled channel i've found, with a constant 60 + people in it every time i join it. pretty easy to find people to play games with, but be warned if you do you'll get a million requests to obs.
koth - koth stands for king of the hill and this is the channel to join if you want in on some king smashin' action. this channel is also moderately popular, with a constant 15 + people online every time i join it.
obs - this room isn't as popular, but its cool because its a really easy place to find games to watch if you're in the mood for sc2 but don't want to play a game yourself. personally i'd like to see this one fill up more than anything, just because sometimes its nice to have some people watching your game. make sure you aren't lagging when you connect to a game though, that's kind of frowned upon (damn you university internet!)
anyway what popular channels have you guys found? does a day9 channel pop up during his casts? how about a GSL channel?
