Well, the best life would (I would imagine) include all the best things that could be had. As far as exclusive things, like virginity and childbearing, the best life would have to choose the better, and I would imagine this is where there would be differences in "best" lives depending upon the nature of the soul in question. At the level at which I can actually grasp, the best life available to most people would seem to be the generative married one. Much higher souls would probably be suited to much higher callings which may preclude childbearing.
Ahh but not everybody likes all everything and thus the best of something may not be appreciated and therefore would not add to the quality of a persons life. For instance, to take an example from something much less important than child rearing, I only like red wine, I've always found this funny because I love fish, but I just don't like the wimpy flowery taste of wines that aren't red (on the flip side I LOVE red wine, even the cheap crappy stuff very dangerous afflication). Even the finest of white wines is not to my liking. Thus, were I collecting the best alcohols I would skip the white wines, there'd be no reason I wouldn't enjoy them anyway (though if I were collecting for resale I would get white wines, they'd be safe no way I'd ever open them).
Just because something is the best doesn't mean you'll like it. While for many child rearing is apparently wonderful and enjoyable it isn't for everyone. If we all took the same pleasure from the same things it would be a terribly boring world no need for variety in anything, no catering to individual tastes. Thusly some people love children, have a bunch, maybe teach or do other things involving kids; and some people loathe children and seek to create a child free zone in their personal space. That's just how it is. Maybe it's a flaw, or maybe that's just how things are.