.22 is better for things like hunting, where .177 might make more sense if you spend more time plinking. .22 is more expensive as well, and has a more limited array of pellets compared to .177.
Remember that the velocity figures some of the manufacturers quote are "optimistic" at best. The light pellets they use to get those high velocity figures often result in really harsh firing behavior, and bad accuracy, where a heavier pellet, and yes, less velocity will make the same gun shoot much more sweetly. I happen to like the "Kodiak" pellet in .177, and my Beeman C-1 shoots it really well. It makes the gun shoot more smoothly than it does with lighter pellets. Yes, the velocity is down a little, but it's very effective if I place the pellet where it needs to go.
Do yourself a favor and look at a Beeman R-9 before you drop any money. It's a bargain at it's price. If you go over the the James Kitchening Forum, aka the "yellow forum" look in the classifieds, and people often have lightly used examples for sale. They even have a "board of inquiry" where you can see what other peoples experiences with your potential seller have been like, which is nice.
Sorry to go all off-topic like that.
