I started buying the Craftsman C3/19.2volt cordless tools in 2006 and they've been the BEST investment I've ever made. I use them on the race car and around the house.
I bought the 1/2' impact wrench when it first came out and it has been GREAT! I can bust the lug nuts off the race car or the trailer in a matter of couple of seconds.
I have only the Ni-Cad batteries (too cheap to buy Li-Ion and charger). I have never had a problem with the Ni-Cads; they seem to last quite a long time and recharge in a reasonble time.
I have the 1/2" impact wrench, variable spd drill, right angle drill, floursecent light, incandescent light, reciprocating saw, jig saw, circular trim saw, 7.5 (?) inch circular saw, leaf blower (jury still out on that, weakest tool of the bunch), drywall roto-zipper, and hedge trimmer. We were amazed at how long the hedge trimmer lasts on a charge. If I start out with the batteries (I think I have three or four) at full charge I've never run out of fully charged batteries no matter what the project. Thought about the chain saw, but haven't had a need yet. I usually but the next tool that is on sale or deeply discounted.
One charger, one type of battery. I love it. Kinda hoping the Ni-Cads would give up so I can get some Li-Ion batteries!
Highly recommend.