The Dalek's know* the doctor as the On Coming Storm, or the Predator etc. But at some point the Doctor started being compared to the Daleks for the wake of destruction he left behind him.
I used to think it was Daleks who used to say this, but I now can't pin down when that was, and I'm doubting whether it was them to begin with...
Who first told the doctor that?
*Spoiler Note:
Not anymore....
This actually goes back to the original series, specifically an episode called, Genesis of the Daleks. Tom Baker is the Doctor and Elisabeth Sladen is Sarah Jane Smith.
Towards the end of the episode, the Doctor is about ready to destroy the Daleks as they are being created. Davros, the creator of the Daleks, in particular, takes joy in pointing out the fact that he and the Doctor are exactly alike, willing to annihilate entire races in order to further their own visions of right. In the case of Davros, it is to get rid of the inferior races, in the case of the Doctor, it is the Daleks themselves.
This ethos of the Doctors gets explored in the rebooted series, and when Davros sees Sara Jane again in the new series' episode "Journey's End," he reminds everyone of the scene.
The first time I remember The Doctor being compared to the Daleks is from the Ninth Doctor episode Dalek --- the introduction of Daleks in the relaunch.
The comparison is not is made explicitly on-screen; Although stated directly by the Dalek, it is only strongly implied by his companion (Rose) that The Doctor's intense hatred for the Daleks makes them similar in spirit.
From Nine's reaction I read that he has nothing to retort and finally is forced to accept.
First accusation made by the Dalek:
Nine: [..] Why don't you finish the job and make the Daleks extinct?! Rid the universe of your filth!
Nine (screaming and spitting): Why don't you just die! (pause) Dalek (calm): You would make a good Dalek.
Later restated indirectly by Rose:
Nine: That thing killed hundreds of people.
Rose: It's not the one pointing the gun at me---
Nine: I've got to do this; I've got to end it [...] I've got nothing left.
The next time the similarity is hinted at:
Rose: [...] it's changing. What about you, Doctor? What the hell are you changing into?
And the Dalek later goes on to note:
Dalek: [...] I am the last of the Daleks [...]
A reference to The Doctor being the last of the Time Lords, and his previous statement about having nothing left.
The canonicity of this comparison might be challenged though, as that particular Dalek was somewhat "broken" and more accessible than regular Daleks since it absorbed some of Rose's features when it regenerated.
