It's worth every penny to hire a professional inspector in my opinion.

I second the professional. Get your own rather than relying on your real estate agent, as the agent may be counting on a good inspection to make the sale, and not use the best. We ended up with lots of unforeseen repairs (inspector checked off on an irrigation system as good shape, it wasn't working, and said the roof was good, it wasn't.). Angie's list, Better Business Bureau, etc will help you find a good inspector.