First name: Dalek
Doctor Who Name Game
Gezz I had no Idea there wer so many eposoids and it went back so long. I have to admit I do not know a lot as this is one of the groups I had to take over after the SA left. I try and read though some of this :)
Mickey Smith ..... I had to look up Season 1 Episode 1 to get Mickey's last name. It wasn't listed, so I Googled it
I've wondered why no one has posted on this. I didn't bother to think about the fact that I left the next person with the letter Y. I looked on the Internet and found better lists of charachters, aliens, and monsters (posted above), and ..... I found YETI!
Yeti from "The Abominable Snowmen" - 1967

Exxilons
First Appearence
Death to the Daleks (1974)
Home Planet:
Exxilon
I had to look this one up but sadly I am old enough to remember the original tranmission and it was a good one... Now what can be done with X? 
Xoanon - a charter (of sorts) from the episode The Face of Evil (Tom Baker)
In this episode DW encounters Leela who has been exiled from her tribe because she has profaned Xoanon, a god of her tribe.
Like DMFW I had to look up this episode and although I remember Leela (who became DW's assistant), I don't specifically remember this episode.

How well do you know the names of Doctor Who characters? Let's start a name game.
The first post will list the name of a companion, main character (like Captain Jack Harness, River Song, etc.), planet, or monster/alien. After that, the next person will use the SECOND letter of the first or last name to list another companion, main character, planet, or monster/alien, but you can't list a name that has already been used. An example would be Doctor and then Ood, or Gallifrey then Amy.
If you can't think of something or someone, here are lists of aliens and characters from (I think) every Doctor Who episode.
Monsters & Aliens: http://www.thedoctorwhosite.co.uk/doctorwho/characters/aliens/
Companions: http://www.thedoctorwhosite.co.uk/doctorwho/characters/companions/
BUT ... if you use an episode guide, you have to list the season & episode where you found the name.
Let's see how long we can keep this going.