I have a set of Makitas, a drill/screwdriver and an impact driver. Two really small and light tools with tiny lightweight Lithium batteries. But it's amazing how much grunt they have and how long the battery lives. It's these two in a box plus a battery charger:
http://www.makita.eu/katalog/showite...temID=DF030DWE
http://www.makita.eu/katalog/showite...temID=TD090DWE
Since there's two of them there's a spare battery at hand.
The impact driver is great for doing wheel lug nuts, winds them up to about 30 Nm and only about a half turn remains to torque them up to 100 Nm.
Cost me about 150 quid for the set. I had them for 1.5 years, no regrets.