Ahhh, a little inspiration from Dougal and SK for this one....
In order of reputation...
ChiangMai Noon - 35 kg (short and bald, it canna be much more)
DirtyDog - 85 kg (Big, but shaggin' keeps him in trim)
DrAndy - 70 kg (He's a doctor, so knows how to look after himself)
Poolcleaner - 65 kg (again, shaggin' does the trick)
danbo - 90 kg (Those clown shoes weigh a lot)
Marmite 105 kg ()
NickA - ????
Frankie - 60 kg (I have no idea, but can't imagine he's fat)
Ice Maiden - 50 kg (I have seen her naked, so I should know, but I don't)
benbaaa - 80 kg
Hillbilly - 70 kg
mrsquirrel - 110 kg (you fat bastard)
GoW - 45 kg