I wouldn't count out the Bianchi Milano. It is a cruiser that has big enough tires for trail riding. It is NOT a mountain bike, so you woud be extremely unhappy on single-track or downhill. But my wife has one and we have gone on park trails and roads and it is very versatile and stylish. I bought her a titanium road bike for an upcoming very long ride we are doing and she is very sad she won't be taking the Milano.
I see no reason to have a off-road-specific bike if you are going to go on-road and trails. Give it a look!
OK, it may be a little out of your price range, but you might want to look on Craig's list.
BTW, it has 26" wheels, like a mountain bike.