Really depends on your goals-
endurance:
the best supp I have ever taken is 8 Beta Anabol by Epic, along with Drive- stuff worked great as a pre-wo/intra-wo boost
Strength:
natural product- creatine phosphate, RPM/Drive, ECA (dunno if that is all natural or not)
un-natural- mestanolone and Sublingual test suspension tabs from IP- I have not found anything better since....
Recovery:
BCAAs, Osteo-Sport (keeps everything running smoothly), NeoVar, WMS, Maltodextrin, Whey Protein
Staples:
EPA/DHA capsules
multi-vitamin/mineral
anti-oxidant
whey protein
lots of water
sleep:
Lipo PM
Melatonin
lean mass:
natural- creatine phosphate, Drive (re-comp), chlorophytum borivillanum santa pau ethanolic extract, HMB (you have to take 8-10 grams/day, but it works)
un-natural- mestanolone