Milwaukee cordless 18V with 1/2" drive and hammer drive function.
It's been my personal favorite for over 7 years solid. After years of borrowing the shop's drill, I finally broke down and bought my own approx 1-1/2 years ago. $250.00 with a FREE Milwaukee/Rockford Fosgate boom box stereo included, that surprisingly kicks ass, even in a loud Ethanol Plant.
Go to Milwaukee site for FREE stereo deal.
I continuously cut, drill, and build electrical panels daily, including conduit and electrical gear installations, driving anchors and blasting holes in concrete, to boring 7/8" knockouts in stainless steel, this thing is a solid workhorse.
Batteries are brutal and powerful. They last for hours on repeated usage. Unbelievably, they charge in about an hour or so (like most brands).
All ergonomic trigger and reverse switching, for one handed operation in tight quarters, but be careful not to let the torque break your wrist.
The battery mounts both forward and reverse. Forward for center of gravity balance at the trigger finger, or reverse for clearing obstacles when needed.
On the down side, there are a couple of things... Just like any drill, it's only as good as the batteries. I had two batteries (out of 6) in seven years go bad. They either got dropped or banged up pretty good (from rotational torque getting away from me) but in both cases, the spot weld broke loose at one of the battery terminals. But the coolest thing is, the battery case unscrews and comes apart VERY easy, exposing the battery circuit for a quick scrape and resolder job. (Not a cheap disposable glue-jobbed battery case like most others.)
Also, my Milwaukee's "hammer function" is nothing like a real hammer function (as found on my Hilti hammer drill), it only has a ratcheting action, that hammers smaller holes in mortar or most concrete... Not good for the big boy jobs, like anchoring 1x6 threaded studs for 20 ton presses or anything like that.
For a REAL hammer function, you gotta have a piston drive that acts like a battering ram. My $500.00 Hilti on the other hand, drills and blasts through concrete like butter... But that's another post.
I own a contractor grade Dewalt cordless too, along with many cheapo's for around the house, and have all major brands at my disposal every day. But for cordless drills, I use no other than my Milwaukee on the job site.
Seriously.