Melatonin is definitely a good sleep aid, and dream aid as long as one hasn't smoked weed prior to sleep.
Although melatonin is non toxic, and beneficial to the organism (as well as being involved in awake-sleep cycles, it is a very powerful antioxidant and immune system booster), taking a 3mg pill increases your blood levels of melatonin 40x their normal background rate, or something similar. Upping your levels of a very important brain hormone over the long term, might not be the wisest thing to do..I mean it is probably fine, but there may be a slight element of side effects in the long term. Ocassioanly is fine I think, but I don't think one should take it every single night.
Some people may find taking melatonin prior to smoking changa interesting...
I can't find the reference, but apparently taking more than 3mg can actually be counter-productive. Meditation before sleep, or physical exercise are natural ways of boosting melatonin levels, as our melatonin rich foods.
Out of everything I've tried, keeping a dream journal is the most potent way of enhancing dreams...I remember them every night, and will have at least one lucid dream every two weeks, just by writing them down.
My most impressive herbal enahnced lucid dreaming was taking a gram of 10x Calea zacatechichi prior to bed (best to abstain from weed for a few days i think, definitely clouds dream recall). I took 2/3 gram in a capsule, and smoked the rest.
I was walking down the street, in some town a didn't know, it was grey and overcast. I was with my housemate and we were walking along, and I noticed that lightning/electricity was arcing from his fingers, hitting the floor and wall nearby..I knew that was impossible, and that I was dreaming...so I ran and ran down the street, and jumped, and was flying... I had not one, not two, but THREE lucid dreams in a row...have never dreamt like that before.