Easiest.
Safest.
*Coolest*.
I will always tend to take Fly for every single character of mine whose concept doesn't strongly demand for some other method of locomotion.
Of course I wouldn't *mind* for its acc debuff to be removed, its speed increased, and whatnot, but as far as I'm concerned, Fly is the definite #1 travel power as it is. There'd be even less reason to take any other travel powers ever.