EDIT: I just noticed that you meant for CCW use - a suppressed MK II is pretty hard to hide. I don't think any .22 is particularly suited to CCW. My advice is to shy away from .22 and look into centerfire cartridges... Even a .380 should be a better choice.
I'd highly recommend the Ruger MkII or MkIII. I've shot a lot of the Walthers - they seem to work, they are cheap, they aren't particularly accurate. The MKII feels like a real gun, shoots where you tell it to, and will last forever.
Poor quality cell phone photo of mine:
A bit of help from Gemtech makes it more enjoyable....
/rl