It sounds like a flat-bar road bike with slightly beefier tires (depending on how much trail/dirt riding you do) should do pretty well. I was impressed with the Jamis Coda line of bikes, although just about every company makes something that'll fit the bill. Honestly, your best bet is to go to a shop and tell the salespeople exactly what you've said here. Take a few different bikes out for a test ride to get a feel for positioning and comfort, and get the one that suits you best.