AEG 18V from b&q. think it's around £79 with 1 batt. £99 with 2. mine has only the 1.5AH batt but lasts quite well. have just got a AEG impact driver with 2 3AH batts which fit the drill as well. good piece of kit, better than ryobi and dewalt. IMO.
edit: and they're Li-Ion.
Agreed. I've got an AEG 18v drill/driver and the same series Impact Driver, Li-Ion, can't fault them. I think they're made by Milwalkee anyway. Go ages between charges and mine take a real hammering, too.