Start with Jon Pertwee then Tom Baker and the effects have been far far worse in the past ;)
The Acting and Character development is what this show is all about not wizz-bang special effects that detract from so many other potentially great shows/movies. There is a reason why this is the longest running Sci Fi series, 27 seasons are now in the history books with 2 more to come(for sure and hopfully many more after that with David Tennet) and its more popular now then ever before :) Of course if you think that Special Effects makes the series then stay away, as there was really only one episode where the effects were amazing and that was 27x02 - The End of the World.