Well for cobraheads I'd say Hubbell makes the best quailty lights but they come with a hefty pricetag... GEs are good quality too and less expensive. Personally, I think AEL is the best value for your money since they're inexpensive, make a good quality light, easy to deal with, and have the most options.
For lamps, I've heard EYE is great, but they're mote for people growing pot in their basements with their specialty wide-spectrum lamps lol... I'd say Sylvania is the best for light bulbs, except for CMH lamps and household LEDs, where i think Philips is the best (yep, Philips!)
for ballasts, i think a ballast is a ballast but Advance seems to have the best reputation...
for photocells I'd say DTL is the best value for your money. Inexpensive, pleasant to deal with, lots of options, and great quality.