I would suggest nothing less than a G4.
I know people on these forums love their G3's but I think the G3 would be to slow for his needs.
Yes I know the G3 can surf the net just fine, but as soon as you start opening up a few tabs and windows, the machine bogs up like hell.
And you might say "Oh well Add som'more ram!" but the OP kinda seems like the type who just wants a no fuss laptop he can just surf on right away.
Not to mention the plague of problems the G3 iBooks had with their graphics cards...
Also most of the iBook G4's came with airport cards (I believe from 2nd rev) so this would probably be the best deal for him.
So go get an iBook G4
You will be very happy!