1.The Three Doctors: A good one. 2 and 3 meeting with 1 is a doozy. I wish 1 could have had longer time but his health impending him, you know a man's gotta do what a man's gotta do. 2 and 3's dynamic make them the favorite Doctor-Doctor dynamic. I wish we could see more of them.
2.The Five Doctors: The biggest Doctor-Doctors ever on Televison. imagine being a fan and seeing five Doctors meet. Well 4. Well 3. William Hartnell had passed on so Richard Hurndall had to take on the role. Tom Baker(the most favorite Doctor ever)declined to appear and eventually regretted it. they used unused footage for him. 2 and 3 bickered and 1 tried to put them in order. 2 liked 1 but 3 didn't. 2 and 3 both liked 5. 5 was a bit nervous around 1. 5 liked 2 and 3.
3.The Two Doctors: 6 meeting 2. One problem with this one. 2 and 6 met for about 5 minutes. I would've loved to see more. 2 didn't like 6 too well.
4.Time Crash: 5 and 10 meeting with Steven Moffat writing it. Man it was the best. Can't wait to see his script for 10 and 11. 5 was 10's "favorite Doctor".
1.The Sirens of Time: I haven't heard any audio but wish I could. 5 and 6 and 7. 7 didn't like 5 and 6. 6 didn't like 5 or 7. 5 didn't like 6 or 7.
2.Zagreus: 8 really liked 7 despite the differences. 8 poked a little fun at 5 and 6 but not much.
3.The Four Doctors: 5-8 and Daleks! What more could you ask for?!!!!!
1.Cold Fusion: 5 and 7. End of story.
2:The Eight Doctors: 8 traveled in time to meet his past incarnations starting with 1 and ending with 7.