Have had good success using Patriot for RAM upgrades and recently used Corsair XMS2 (I think that's right) in my new build. Very happy so far!
Also used Kingston "system specific" memory to upgrade one Dell Dimension and although I can't say much about the speed, it's worked perfectly with no problems for over a year now.
I just ran into a problem with a set of DDR 184-pin G.Skill the other day. Value series to be sure, but the info on NewEgg and even on the outside of the package indicates 2.5V, but the actual sticks are labeled 2.6V-2.75V. System boots, runs most Aps OK, but no luck with Photoshop (program fails to initialize)! Have to return/exchange. My first experience with G.Skill and sadly, probably my last as well.