What I've tried:
Ambien - good stuff, but I wake a little groggy.
Valium - ugh, hangover city.
Xanax - see above.
G - nice, but too problematic.
Valerian root - love this stuff. Works really well.
Melatonin - had horrible, lucid nightmares with this stuff. Never again.
What I do now: A few exercises from an old tantric yoga book. Deep breathing, coupled with tensing of the muscles in each group, individually. Tense, then relax, repeat with next group. Go from the feet to the head. It doesn't knock me out, but I sleep REALLY well, and can pop right out of bed the next morning.
Sounds crazy, but hey, it works like a charm for me.