I think I'll add to the fray here.
First off, my pride and joy, the baby I lovingly put together from parts and pieces, finally completed and kicking some serious rear end! Here she is, in various incarnations:
Next up, I've got my 2k9 Tippmann A5. I've put a few simple upgrades on her (inline reg at 400psi, CAR stock for the remote, bought a new Low Profile hopper, 16" Stiffi barrel and RAP4 barrel adapter, Daisy red-dot sight, removable bipod that I never use...). All in all, I have around $175 invested in her, including the purchase price! Pretty darn cheap for a rifle of that quality! No performance upgrades, probably never will. Maybe Squishy Paddles if the right price comes along.
Finally, my Viewloader High Voltage. Looks can be deceiving...that baby will shoot 15bps at 290+/-4 all day long. An ACS bolt makes it impossible to chop, and with full-automatic, it's fun to shoot purely for psychological advantage!
Oh, my 2k0 AutoCocker. Second gun I ever owned, and I learned everything I know about airsmithing from this baby. More leaks than you could shake a stick at and when she did work, she shot like a babe. Here she is:
I've got five more, but they're boring...