My top 5 would differ from most people's top 5, but of course, there's always a couple staples, like creatine & protein powder. Beyond those two obvious ones, I would say fish oil, green tea extract, ECA/NYC, NAC/milk thistle, & multi-vitamin/mineral.
HMB is decent when used with creatine, they work well together, I have a couple studies on this somewhere....
Zinc & Magnesium are only good if you're basal levels are low in each, I dont see something like ZMA as very beneficial, especially for the pricetag that accompanies it.