Kingston is a pretty popular brand, but I've never owned them. I just bought new memory, and was researching as much as I could on memory. I've never heard of kingmax until a couple of days ago...they're apparently one of the cheapest brands available, but at least for my mobo, kingmax made it on the qualified list.
I was going to go for Geil, but I didn't see them on the list. From what I have found, Geil requires alot of voltage (everyone has to run them at 2.8V or else they won't work). If you can't adjust voltages on your mobo, then this isn't an option.
(BTW, if you were curious, i went with OCZ. They're popular with overclockers now...it was really, really expensive, but worth it for me...I can overclock and still keep lower latencies.)
As for latency, you want the lowest latency possible. Lower latency usually means higher prices. On my old ram, I tried benchmarking with 2, 2.5, and 3 CAS...and the differences are a bit noticeable.
Newegg.com has ram available in both their refurbished and their clearance section. I was going to get the pc3200 kingston ram there, but decided to go with the ocz instead.