I'm a cycling newbie as well. I opted to build my own frame since I'm a DIYer...and felt like buying pre-packed bikes is a rip. (They often package lower quality components)

I ended up getting a cyclocross frame. The geometry is a little more upright which is nice for someone that isnt a season cyclist, although not as upright as a MTB. Right now my bike is more like a road bike (carbon fork, 700x23c wheels/tires).

For commuting/joyrides, this bike is perfect. I dont deal with the stretched/slouched geometry of a road frame...and if I swap my fork/tires I have a good ATB that I can hit trails with.

I'm riding the Nashbar X cyclocross frame (which was only 80 bucks during a double sale) with Shimano Ultegra stuff (105 shifters.) I constantly pass roadies on the trail...: P