The bad news is that you will get as many different opinions as responses. The good news is that there are no wrong answers and whatever you choose will likely be a winner. That having been said, my perspective is:
As gfw1985 said, the standard auto with a 5.5 inch target barrel is a good choice. My mark II will shoot as well as my friend's S&W 41, at 1/3 the purchase cost and without the ammunition sensitivity of the model 41. The downside is that the takedown on the ruger standard auto is more complicated than the buckmark or other autoloading handguns. However, I've found that after you do it a few times and learn the tricks and after the bolt stop pin loosens a little, the dis-assembly is not as daunting as you would initially think.
As wwb, said, the double action SP101 is hard to beat. You have 8 shots, and can load and unload it more quickly than a single action revolver. Some find the hi-viz front sight a little garish, but with my aging eyes, I like it.
There is also the single action, single six revolver. The big advantage is that it comes with an extra cylinder chambered for .22 Winchester Magnum Rimfire (WMR), which represents a big step up in power over the .22 LR. My chronograph tells me that most .22 magnums run between 1300 and 1400 ft/sec from my 4 5/8 barreled single six. That's .22LR high velocity RIFLE performance, from a handgun. If you don't need that power, then use the .22 LR cylinder. Incidentally the Magnum cylinder will also chamber the less common .22 Winchester Rimfire (WRF). It's sort of a mid-range cartridge between the .22 rimfire and the .22 magnum. Both winchester and CCI make the .22 WRF.
There is also the single action ruger bearcat. It's small and elegant, but comes in .22LR only. No .22 WMR cylinder.
My choice would be either the MK series with a 5.5 inch bull barrel , or the single six, or ideally both.