I use Energizer Lithium ultras in my Cuddeback cameras. They are out year round even in the Wisconsin winter. Not as many pictures in winter, but I would say average out to 100 pictures a week, per camera. I get a year and a half to 2 years out of them. each camera takes 8 AA's.
If you don't mind the pain in the back pocket, Lithium Energizers are hard to beat. I loose tract of time as to how long they last. The one camera is set to take 3 pics and 30sec video and I'm sure its been close to year on the batteries. And they handle cold really well. I did one time get a bad batch from Wally world that only lasted a month but all others have done great. My son does the rechargeable 6 volt route and those last long also.
Also check out jet.com, was able to find the ultimate lithiums at a really good price there as well. Have a plotwatcher taking a picture every 10 secs that I put batteries in over a month ago and still shows 100% battery life. Best I've found and they seem to work better in the cold and are lighter as well.
I like the lithium ones as well. They are expensive, and can be hard to find (damn meth-heads) but they are what I use when I want the batteries to last for a while or under more extreme conditions like in the winter cold. Cold seems to really drain a battery. Obviously how much camera activity you get will determine how long they last for you, but they seem to work for me.