Should I ride fixie ir roadie?

i love to ride bikes and have been riding seriously (health benefits and commuting) for about three years now, however i have been riding a hybrid bike. now i no im ready to move up a notch, with speed and overall coolness. I've been dreaming of a fixed gear/single speed (flip flop hub) for so long now, but i don't no if this would be best for me, i tend to commute for 4 miles a day, 2 to work 2 back home, and i use to skateboard so I'd love to be able to do tricks on a bike, however i have a nice hill i need to conquer and so dodgy pot holes. would a fixed gear/single speed be ok for this? bare in mind of the hill and the fact that i would like to do tricks, or should i just get a roadie?