Revolver
pros: simple design makes them easier to use. less moving parts make them nearly impossible to jam. robust build means more powerful cartridges are available to use in them. Interchangeability of cartridges; many larger revolver cartridges are just longer versions of an older round (.357 Magnum will hold .38 Special. .327 Magnum will hold .32 S&W Long and .32 S&W. .22 Magnum will hold .22 LR and 22 Short, etc etc)
cons: low capacity, long reload time (unless you practice practice practice with moon clips, but they're still cumbersome), thicker due to the round cylinder, slow to fire (either a really long trigger pull is required to both bring back the hammer, rotate the cylinder and then release the hammer all at once, or you have to manually pull back the hammer to make firing easier-also slow).
Semi-auto pistol
pros: high capacity, fast reload, trigger pulls are usually much easier/shorter-but this varies from gun to gun, depending on what type of trigger you choose
cons: more moving parts, less user friendly (but you should get to know your handgun inside and out. so this is a weak con), more prone to jam (however semi-autos have gotten exponentially more reliable in the last 30+ years. Arguing reliability in any modern semi-auto is a moot point, but a revolver will always have that slight advantage), generally weaker cartridges available.
Another thing I want to mention is research and training. Judging by your lack of knowledge about revolvers and semi-autos, I think it's safe to assume that the names of all of those calibers are totally over your head except maybe .44 and .357 Magnum. If that's the case, once you decide whether the revolver or the semi-auto is a better fit for you, you need to do research on calibers before you choose your weapon. You need to take into account your budget, availability and power. Handgun cartridges are as varied as the handguns themselves, ranging everywhere between .22 CB, which is barely more than an air rifle, to .500 Smith & Wesson, which will just about break your hand, and ranging in price from 17 cents a round to several dollars per round.
What you need to do is first find out what are the most common cartridges (so you don't have to scour the Earth for ammo), then find which ones you can afford, and which ones you think you can handle. Then, go out and try each one, and see which one you like the most/can handle the most accurately. The general rule is to carry the largest caliber that you can shoot accurately. A hit with a .32 is much more powerful than a miss from a .45.
I'll go ahead and tell you that you'll find out that these are the most common handgun calibers you'll find in stores:
Revolver
.22 LR/.22 Magnum (.22 Mag isn't as common, but there are a lot of revolvers chambered for it, and you can always put .22 LR in them), .32 S&W Long/.327 Magnum (I'll admit that the .32 range is not THAT common, but it seems to be growning in popularity), .38 Special/.357 Magnum, .45 Long Colt, .44 Magnum/.44 Special (a poor carry choice, but a sound HD choice if you don't need to worry about over penetration)
Semi-auto
.22 LR, .32 Automatic Colt Pistol (ACP or Auto), .380 ACP, 9mm Luger/Parabellum, .357 SIG (a bit of a pricy, niche round, but it does have its followers and I do always see it in stores), .40 S&W, .45 ACP
And finally, whatever you choose, practice practice practice. If you're going to use a tool with the intention of trusting your life to it, you need to know how to use it well. This is why caliber choice is so important. If you choose a caliber that's too expensive or too unpleasant to train with, you won't and you won't be good with it.