I got my wife a Ruger Single Six, 5-1/2" ss with fixed-sight and ivory polymer grips for her birthday. It was used, but shoots incredibly well with both the 22lr and 22wmr cylinders. She shoots it better than I do. I was sorta hoping she would hate it so I'd have to keep it and buy her something else.
My favorite 22 handgun, however, is my Smith 648 22wmr with 6" barrel. I wish it were a 4" barrel, but the underlug and longer barrel prevent the revolver from jumping at all when shooting, and it is obnoxiously accurate (much more accurate than I am). Plus, it handles like my 686-4 2-1/2", and 686-2 4". I can practice with the 648 for about $11/50 22mag rounds, and know that the trigger pull, grips and sight pictures are essentially identical to my carry guns. I really like the 22mag round. It's not given much credit, but it's a nasty little critter (especially when used on nasty little critters). I sold another 648, earlier this year, hoping to pick up a 617 10shot 4" or 6"er, but that didn't happen. If I can find a reasonably priced 650, or the above mentioned 617, I plan on rounding out the family.