My first 9.6v Makita NiCad battery packs lasted about 15 years. Sanyo NiMH AA's last around 10 years when they get to the 80% capacity mark and I give them to the kids. Energizer and Rayovac last 5-6, Radio Shack are more $ than the rest and last 3-4.
Anything Lithium Ion 2-3 years at most. I make sure if I'm buying a GPS, Radio, Camera, etc to buy the AA powered rather than the lithium ion.