Ok, so I'm planning to buy a IRO Mark V, but can't decide on a fixed gear or a single speed.

FIXIE
Pros:
-Total awesomeness
-Skid till tires are burning
Cons:
-Going downhill (or just let my legs hang?)

SINGLE SPEED
Pros:
-Coasting
-Speeding...downhill
Cons:
-No skidding!
-even "Fixie" sounds better


HEELLP!

oh and what differences do the cranks and cogs make?