My 'first' drill was a right angle Makita 7.2V NiCD that my father had, but the first drill I bought for myself was a Milwaukee 0624-9 1/2" 18V NiCD hammer drill. Coming from having only used the Makita, I was extremely impressed with its power and capabilities.
I quickly upgraded to Milwaukee's V28 (now M28 line) and still using the tools today, almost 15 years later. I have since upgraded to M28 batteries, since I didn't use the tools for a few years and let the batteries brick themselves from low cell voltage. I am still VERY impressed with the power of their bandsaw, SDS+ hammer drill, 1/2" impact wrench, Sawzall, etc.
Today I have quite a mix between Makita and Milwaukee and love both. My daily carry is Makita, but if I need something special / trade specific, Milwaukee is my go-to.