i use a G7.
the G5 has a click scroll i think...the G7 does and i believe they are the same with the exception of course that the G7 is wireless.
if you want a wireless gaming mouse, G7 is by far the best IMO.
wired mouse, i agree with poster above me (who obviously works for logitech lol jk) mx 518 or a G5. i have tried the G9 and didnt like it at all.
salty's idea is the best. go hold one.