Ok thanks for the input, sounds like I better just stick to airguns.
WM, I was in your exact same situation... in retrospect I would not have spent as much money on airguns as I did. Once you move to rimfires you might never turn back!
For your purposes, you want a bolt action rifle. I'd suggest a CZ 452 with a long barrel, but there's a wide selection. A Super Aguila round will be virtually silent out of a long barrel and pretty quiet even out of a "short" 18in barrel (definitely more quiet than a pnuematic air gun or magnum spring air gun).
With accurate placement, Super Aguila can take down squirrels... unfortunately I don't have a rifle that likes that round for accuracy... I get "Minute of Soda Can" if you know what I mean (but that's good enough for squirrels with in 30 yards). The main pleasure is quiet indoor plinking without the annoyance of pumping, cocking, or single loading pellets.
If I need accuracy or a bit more "oomph" I'll use CB Caps. They're very accuate in my CZ 452 Varmint and are about as loud or quieter than my Steroid 392 on full pumps. The 392 has a "sharper" crack to its sound while the CB Cap has a deeper "boom" to it (again, both are very quiet and- used to dispatch an occasional pest- your neighbors will not notice or complain unless they're looking right at you). Heck, if your neighbors don't know about guns and- for whatever reason- bother you, you can always just say you were shooting an air rifle... they're likely not to know the difference.
For quiet rounds, a bolt action rifle will cycle and eject flawlessly and faster than a semi-auto where you have to manually cycle the bolt. You could use a pump or lever action alternatively, but, IMO they don't scope as well and levers in .22 can cost quite a bit more and are more mechanically complex/prone to jams.
Anyways, get a bolt action rifle and I believe you won't regret it. People like us love shooting but are hamstrung by the law and social stigma (neighbors) so we've been enjoying air guns... but rimfires simply let you enjoy what you actually like- shooting- more.