The vast majority of airsoft guns are spring, electric, or propane powered. You're right about the accuracy, although some are usable (for hitting, say, a coffee-can sized target) out to 40-50 feet. They're fun for plinking, althought the .12 gr BB is really kinda useless outdoors. Most are also useless for scaring away animals (except birds), cats and dogs only get slightly annoyed if they're hit at close range. More than 10-15 feet away, they might not even feel it since plastic BB's shed velocity so quickly. For that, you're much better off with a regular BB pistol.
Most guns give a backspin to the BB which greatly increases the range ("hop-up"), but that also means that unless the hop-up is adjustable (an unusual feature) the gun will only shoot properly with one weight of BB.
To a large extent, it comes down to this: how much do you want to spend?
Actually, I'm not even sure this is really an acceptable topic for the forum... so if the moderator gently taps you on the shoulder you can email me and I can give you more suggestions.