I use both a Makita 18 MXT combi drill and a 12v Dewalt XRP Combi. (Models 8444 Makita and DC945 Dewalt)
To be perfectly honest there is little difference between the two. I looked at both standard range Makitas and Dewalts but once you get them in your hand the XRP and MXT really makes a difference in build quality. I believe they use full metar gearing so wear is reduced, also the Makita has user replacable brushes, not sure about the Dewalt (Will have a look in the morning)
If your not too fussed over the very latest LXT (Lithium) technology, you can grap some great deals on the MXT range. I picked up a second 18v combi drill, 2 x 2.6NIMH batteries, charger, case and free Makita torch for just under £170 from ebay the other week delivered.
I cannot remember a time when a battery didn't last a full day.
I only bought the Dewalt because I had bought the DC011 radio/charger for work and thought it wouldn't hurt to use the drill purly as a screwdriver. The drill and 2 batteries was £100 new and has been worth every penny.
Luke Scotty - How can you not use those lovely Knipex everyday? It's what they were made for!!!!!!