I first experimented with valium recreationally, finding it to be of little interest; the effects were short-lived and lackluster. However, during this time I was in a full time clinical rotation with 15 credit hours of coursework and a 35 hr/week job and I could never fall asleep soon enough to get 7 hours before waking up at 5:30 A.M. Valium proved to be a beautiful solution to this problem.
Regarding its use as a sleep aid, valium is potent; I was always asleep within 5 minutes of snorting it, without fail. Perhaps its most attractive feature, though is the short duration of action. I only needed help FALLING asleep, and once I did, the valium would soon wear off, allowing a normal sleep cycle. It is the only sleep aid that I've ever taken without some degree of hangover.
It is worth noting that I only took valium the nights before I had early morning clinicals, to avoid the risk of dependance.