As far as the "Unlimited" issue goes. You should always be weary of a host offering unlimited space, or unlimited bandwidth. Those are things they have to pay for and therefore there is a limit, depending on how much you/they pay. Other features though, such as e-mail addresses, subdomains and the like, are a little different. Before I go on, I will say, I know there's a limit to everything, but for a lot of these added features, the limit is so high, that it doesn't really matter to the user. And besides, you'll most likely run into webspace or bandwidth issues before you run into "too many subdomains" issues.

Basically, when a host offers "unlimited" options, look and see what the cost of those options are to the host, and if it seems like they're doing overselling. If not, you'll probably be in the clear.