I own 2 18v DeWalt drills one is about 8 years old the other is 2. I have never found a fault in either of them. Tons of power, good weight and a great feel. I also own a 14.4 that I use at work. It takes alot of abuse, drilling through steel and concrete. Another awesome tool, however, it is an XRP model and quite a bit heavier duty than the standard.
Personally, though. I would go with the 18v unit.