Hmmm... haven't watched much of GT but DB was actually the first anime I ever watched. It was actually one of the 2 only anime available to me at the time. The other one was Sailor Moon.
DBZ was also very good, although I found it to be very repetitive after a while, and some parts were needlessly long... I didn't like this because if an episode was boring or filler it meant I had to wait another week for the next episode with the exciting part.