Wishing I had the libido I had at 20, the health that I had at 30, and the wisdom I think I have now. Eh, what the heck!
At nearly 47, my libido is stronger than it ever was at 20. In fact, I have a much greater appreciation of women in general now. Looking back, I was way too picky throughout most of my 20's.
It would be nice! And a woman to share it with!
Not sure I'd want be young again with my current knowledge, as I'd likely never marry or have kids.
I'd just grab a few master degrees and live overseas, be a totally different person than I am now, and my kids would never have existed...not good.