From all I can gather, the issue has to do with some sort of bug in the 10.7.4 code for controlling automatic graphics switching. -Particularly after installing any program that makes use of the graphics switching capabilities.
In my case, resetting the SMC wasn't enough. -I also had to (re)toggle the Graphics Switching setting in the Energy Saver section of System Preferences. -The box should be un-checked, then re-checked, then system restarted.
I've been consistently getting my usual 6 - 7 hours of battery life for the past 2.5 weeks now.
I also did install GFX Card Status and hard-switched the graphics mode to internal only, and it immediately lengthened the battery life... So that's when I realized that Lion was switching to the high performance graphics processor, even when running on batteries. Note: I am not currently using gfxcardstatus... and still getting the normal battery life. -I just installed it for trouble-shooting purposes.
Again, this may not work for every one, but it's worked for me.
-L