It all depends. The important thing is that you first assess your needs. It is important that you get what you need from a Web Host without paying for services or features that you will not be using. The vast majority of people can get by with a cheap web host. If you have a site with average traffic then most web hosts can easily meet your needs and there's no reason for you to spend more than even $10 a month or so.

The key again is to evaluate your needs: disk space, bandwidth, technology (PHP vs ASP, MySQL vs SQL Server or other database, blog features, etc). Look at what web hosts offer what technologies and features and go with one that has what you need but doesn't cost you much.

Remember, it's usually easy to upgrade your service as your needs increase, but why pay for resources you are not using.