Ryobi 18-Volt P855 Combo Kit $49 at Home Depot

If there are no fries or a Coke included, then this is not a real combo deal...

Much better combos than this are out there. I got the full Ryobi set with case years ago and it has been good except the NiCad batteries are disappointing. I got a good mini Ryobi combo deal that had a newer drill with charger and battery to make the switch to lithium ion batteries and is a big improvement. The lithium batteries are more spendy but worth it.

Lithium batteries only have a shelf life of 2-3 years regardless of how you use them. Way over-rated unless you are a professional contractor. Dewalt Nicads are better than most other brand's lithiums.

If I don't store the battery on a shelf, will it last longer?

You can store Lithium cells in a partially charged state in a refrigerator to make them have a longer shelf life, but I don't know anyone who actually does this... maybe some of the battery nuts on candlepowerforums.com do. I'd peg Li-Ion shelf life at closer to 4-5 years tho', or less with regular use.

NiCd definitely last longer whether used or sitting on a shelf, but the main thing I don't like about them is any with relatively good energy density have rapid self-discharge so if you haven't charged 'em within a week you probably want to do it before use.

I wish Sanyo made sub-C sized Eneloops. Even better if they came from the factory with tabs already welded on both ends.

Ah ha, so refrigeration is the key. So the shelf effect is somewhat countered by cold temperature storage. BTW, can you confirm that the refrigerator interior light actually goes off when you close the refrigerator door?