I had the same kind of LASIK you are having done about 2 mo. ago. I am 36.
The results greatly exceeded my expectations. With current prescription in my glasses, I was a weak combined 20/20, but my right eye (the one I use for shooting) was weaker. Without glasses, I was practically blind, with my perscription in the low 7's in my weak eye and high 6's in my "strong" eye.
I am now 20/15 with both eyes about equal.
I had the proceedure done stone cold sober. No problem. Not real comfortable at times, but no real pain either. I have more discomfort from a routine dentist visit.
I would save the valium for after the procedure. My eyes burned pretty good for about 4-5 hours and I needed help going to sleep. When I woke up, no more burning and I could see quite well. I drove the very next day with no problem.
I did have intial trouble reading (and computer) for a few weeks, where long term use would give me a pretty good headache. That has now resolved itself. I also had some eye dryness, but that now has past. Just figure to give yourself 1-2 months for everything to get back to normal.
I shot my first service rifle match with the new peepers last Sunday and I surpassed my highest score ever and won the match (after a winter of no competitive shooting). The sight is definately better than with glasses, which I did not expect from this surgery.