New Set of Batteries for my Camera

I'm about ready to buy another set of rechargeable batteries for my DSLR camera, the set I've been using has lasted me near 4 years, they no longer hold a charge for very long, so it's time to replace them. They really are a great investment, I can only imagine how much I would have spent on batteries for that one camera over those 4 years if I didn't go rechargeable.