I'll cast another vote for the FWB6xx series. I've had my '600 for about six months now and it's a lovely thing - consistent to 3-4fps, easy to cock, high build quality, reliable and, of course, very accurate in the right hands. The first '600 models lacked some of features later found on the '601-603 ones but don't let that put you off as it'll still outshoot you all day long.

It instantly became one of my favourite airguns and the one I look forward to shooting the most.