First, I think it is important to maintain an even temperature (no big temperature spikes up or down.) Actually, bulk aging helps with that as the bulk wine maintains its temperature better than individual bottles of wine.
Second, I try to maintain a temperature between 65 and 70 degrees in my wine storage area. This is difficult for me because I don't really have a heating/cooling system dedicated to my wine storage but I do try to keep the temp in that area in that range.