I own 3 revolvers, and I wish I had bought differently...
I started with a Ruger SP101 3" .357. I wanted a lightweight, small revolver with a good punch to it. Backpacking gun. I'm a pretty good shot with it to about 50ft, which is all I ever intend to shoot it out to. I don't regret this gun, but I will get to my point in a second.
I followed up with a Ruger Redhawk .44 5.5". I have since decided that I don't care for the grip on it and I have ordered a hogue hardwood grip. I am waiting for delivery right now. I have pretty good-sized hands. I find that I don't like my middle finger being mashed behind the trigger guard, and the hogue closes off that space. I have also found that the trigger on S&W's is much smoother with stock guns, and I will probably have a trigger job done on my Redhawk.
I got a taurus 9-shot .22 DA revolver 5" around november of last year. I again don't care for the grip on it at all. That being said, I have not changed the grip yet... will probably do so in the next couple of months. This little guy has been very good at teaching me how to shoot a revolver smoothly with a DA trigger pull. The trigger pull is very stiff on it (I'd guess over 15lbs) but that is because of the short cylinder travel per trigger pull, I think. Get a six-shot cylinder if you want a .22.
My point is, get a .22 first. If you're enough of a gun nut to post here, then you WILL end up owning more than one gun. Learn to shoot a DA revolver reliably out to 25 yards. Get a decent length barrel. The longer the better, especially on a .22 that you won't end up using for self-defense most likely.
After that, think about whether you are going to hunt with a pistol. What game are you going for? Or is this human defense? Everybody can handle .357 with a little practice, maybe even .41 magnum. Fewer people can handle .44magnum or larger magnums (.445, .454, .480, .500, etc.), and lots of places in the US don't require that level of power. How much fiddle-farting can you stand with moon clips? If you have a .45acp or 10mm, Taurus, Dan Wesson and Smith and Wesson make revolvers that will shoot those cartridges, but moon clips are unpopular with some shooters.
Also, consider what brand of full-size revolver you will probably end up with. If you want a Ruger GP100 in .357, look at the SP101 4" .22. If you want a Taurus, look at a similar frame design in .22. Try to buy a .22 that matches your intended centerfire wheelgun.
Don't buy the big wheelgun before you have put at least 5000 rounds thru the .22, however. You'll be much more accurate after getting a good feel for how your revolver's trigger works and how much wrist strength it takes to shoot a DA revolver accurately.