We still have our GC hooked up. Eventually I would like to get the wireless controllers so we don't have to worry about having 3 systems (GC, Wii, PS2) hooked up. Plus if we ever get a 360 it will have to go.
Plus now that the Wii (unlike the other systems) is basically a part of our entertainment center, we don't really pull it out to play it.
The PS2 and GC are under the TV and can be pulled out when playing.