I don't actually know all that much about guitars, but the best advice in buying any instrument is to go somewhere with a lot of choice and play lots of them and take the one you like the sound/playability of.

Beware of buying a cheapie you can bash around without worrying about it. If you're sentimental enough you'll end up falling in love with it however flawed it is. My emergency stopgap busking violin has been with me for four or five years now and its been all over the place with me. I might buy a nicer one once I've got the money, but the cheapie has far too much sentimental value now for me to be blase about it getting knocked around.