I'd go with the g7. I tried the g5, g7, and Copperhead. I preferred the cordless. I had a friend who switched over from the Copperhead due to him having problems with his--I think his eventually stopped working.
The Copperhead's firmware update process is a little more involved than just click and go. I kept having the issue of the mouse not being recognized when I restarted. I had to unplug and plug it back in for XP to see it.
I'd go with the black g7 with textured sidegrips here. My only complaint about the first green/silver version is glossy side finish.
G5 or new G7, hands down. I have both (got the G5 for $20 with that Amazon rebate a while back), my sister uses the G7; the only reason I don't use the G7 is I hate the finish. Will probably pick up the new one sooner or later.