If you are going for a new bike, the Releigh Misceo is a good choice. It has a rigid Chromoly fork, which is my personal favorite. Its OEM tires are also good multi-surface tires, so you wouldn't need to switch tires like you may need to on a mountain bike. The problem with getting a new mountain bike is that you will certainly be a getting front and/or rear suspension, which wouldn't be the best fit for the riding you describe. Suspension forks tend to be a subjective item, as some people like them and some don't. I only like my hybrid's suspension fork when I ride on rough, washed out dirt paths with my son. Otherwise, I wish the bike had a rigid Chromoly fork.

If you decide to go the used bike route, you may find a hardtail mountain bike with a rigid fork. Then you could put a good set of multi-surface tires on it (like Serfas Drifters: http://www.serfas.com/product_details.asp?ID=558 ).