I voted for 10-15 seconds, because I would like to have the
option of using decent acceleration if I decide I really do need it. (Or want to use it, rarely, just for jollies.)
My usual 0-60 time is "No".
I very rarely drive 60 MPH, and generally take a loooooong time to get there if I do. I'll generally try 50 MPH or 55 MPH on the freeway, and only decide to try 60 if I think I'll be causing problems at a lower speed.
-soD