There's a nice preview of the new 2010 series online now...

http://www.bbc.co.uk/doctorwho/newyear/

The first regeneration I saw was Tom Baker to Peter Davidson. I'd never heard of regeneration before, and don't think I knew other actors played the Doctor before. One of the biggest WTF moments of my life!

I remember when Tom Baker regenerated into Peter Davidson. I was so into Baker that I abandoned Dr. Who altogether for a while. Luckily, I did manage to catch Davidson and developed a liking for his Doctor right before Colin Baker took over, then I dropped out again! I didn't find Who again until Sylvester McCoy regenerated into Paul McGann in the American Who movie. What a ride! I'll be a bit more patient with Smith.

My first recollection of a regen was from Tom Baker to Peter Davison. I was SO annoyed at the idea Baker was leaving that I didn't watch Who for a number of years afterward.

I've rather regretted it ever since, which is why I've been advising the "If Tennant's gone, so am I" crowd to reconsider and give Matt Smith a chance.

Oh, and I'm another member of the "Colin Baker got shafted" brigade.

Patrick Troughton was the first Doctor I can really remember, so for me he's the definitive Doctor, with the Ice Warriors, the Krotons, and the Cybermen :) Jon Pertwee was a bit of a shock to me, and I don't think I've ever appreciated his performance as well as he deserves.

I started with John Pertwee, and have watched ever since. As much as I love David Tenant's Dr, I am still the most fond of Tom Baker.

I agree with jasonite...Please don't say "contrary to most fans". Here in the USA, Colin Baker is very well loved, both as The Sixth Doctor, and as his own charismatic self.

Although I am very fond of David Tennant, Colin Baker IS the Doctor at our house, "whether you like it or not". In fact, last Thanksgiving, my husband and I drove from Buffalo, NY to Chicago, IL to see him at Chicago TARDIS...with our now-nearly 16 year old son, who is (not coincidentally) named Colin as well.

My first Doctor was Jon Pertwee though I must say Tom Baker was my favorite.

My first regeneration was Tom Baker into Peter Davison. I had watched reruns of the previous Doctors so I knew he changed every so often. So it was not much of a shock when Tom Baker's Doctor regenerated. At first I was a little upset and all but I got over it. In time I had come to see the regeneration as an exciting time. I knew we'd be betting a new Doctor which made it exciting. I will miss Tennant's Doctor but I do think its time for a change. I know it will be hard on the new Dr.Who fans.

The first one I saw was Tom Baker to Peter Davison. While Tom Baker is still my favorite, I didn't have any trouble adjusting to the new Doctor since I was a Peter Davison fan already (from All Creatures Great & Small).

I liked Colin Baker much better than the one after him. That is when I stopped watching.