Not sure that 10 is enough!- I'll do my best

1) The king- Crosman 2240. A hobby within a hobby. I defy anyone to say 'It's finished'

2) Crosman 600- nothing more to say- anyone into airpistols MUST HAVE one of these. It's the law!

3) Diana\Original's I have and owned

P5
LP6
Mod 10

Still got them

4) CO2-

Webley MKVI (pellet) very good
Colt SAA (pellet) Excellent
P08 (KWC) utterly superb beyond belief
Colt M1911A1 collectors edition- very nicely detailed pistol- and original Colt walnut grips will fit with a little work

5) sorry but I have to go over 10 -

10m pistols-

other than the Mod10 already mentioned- a special nod to:-

FWB 65
Alpha CO2
Baikal mp-46m
FAS604

And a lot more!