i use the makita 18v lion drill's they have been as good as gold i got an impact drill too for screwing screws in as it's sooo much better than using a drill driver, i got my set second hand off the bay for £215 all in and i give it a right battering at work and it doesn't miss a beat, i'd stay clear of dewalt as i'v found they are just hyped up in general, hilti are one of the best as well as panasonic but the price is also high end, i'd go with makita all day for the price and reliability and build guality

bosch are also a good drill but in my years i think makita just slightly swing it as a better drill