I’d want a prehensile tail, but I’d want it forked halfway. That way I’d get a lot more balance out of it when used for utility functions. Having two tail-ends would be useful towards freeing myself if I was trapped. Each end could wrap around something so I could suspend myself in trees/ropes/etc. They would be able to assist in lifting/carring heavy objects by having my tail come out from between my legs (yeah the concept seems nasty) and use the tail-ends to wrap around/push up on the heavy object to help support it. It would make dressing/undressing quicker as it would be as if I had an extra pair of arms to put stuff on/hold it in place. I could use them to massage my shoulders or brush debris off my back. Having two tail ends would also be useful in restraining someone.
I’d want a fox tail.
It’d be fun.
That I would love to see! 
for me…prehensile would be cool, but since that’s been done to death. How 'bout a stegosaurus tail. I like shiskebabs, & if somebody fu**s w/ me, I’d just stick it to 'em.
Mine would definately be a kangaroo tail. But with a hand on the end, so I could grab stuff too.
roadkiller you could be one helluva shoplifter if that tail came w/ the pouch too.
Humorist H. Allen Smith wrote an entire book devoted to the social effects when people suddeny start to be born with tails. The Year of the Tail is out of print, but well worth looking up.
As for my preference, I’d of course want a prehensile tail, while noting tht a prehensile tail strong enough to be useful (i.e. – it could pick me up) would be a pretty thick and probably ungainly looking mass of bone and muscle.
And I agree with Jack Chalker that Horse-like tails look very sexy on women.
I brought this up to a friend of mine once and she just looked at me weird and said that people with tails would be sick. Clearly the girl has no imagination.
I would go with monkey tail with hand on it. It would be furry and PURPLE!