By the way, Steelharp, I have a Gamo Shadow 1000, and I really like it. It shoots extremely well, and came with a set of Tru-Glo fiber optic sights that are about the best that I have used. The dots are smaller than on most of the others that I have seen, allowing very precise aiming. The Gamo 1000 is in 4.5mm (.177"). I also have a Gamo Hunter 440, a RWS Model 38 and a RWS Model 52, all of which are 4.5mm guns. The one that I almost always grab to lay pesky varmints low with is the Gamo Shadow 1000 (which is just a plastic stocked Gamo 220).
Whatever rifle you finally decide to get, use good pellets. I use mostly RWS Meisterkugeln (or however it's spelled) or the economy Geco pellets. The flat target pellets are generally more accurate than the pointed ones. For example, the RWS 38 is very erratic with the RWS Superpoint pellet, but is extremely consistent and accurate with the target pellets. You might also try the Beeman Crow Magnum pellet. It's quite heavy in 4.5mm, and will keep the velocity a little lower, but with increased bullet energy. As mentioned above, velocity, by itself, is not everything. But I'd rather have as much as possible as not...
Whatever you end up getting, have fun...
I also have an extremely cheap Chinese air rifle, which is really junk. I can't speak to the rest of the ones that have been mentioned here. However, although I have great respect for the Chinese in many ways, I'm not planning to buy any Chinese manufactured airguns...