Every doctor apart from the Eighth Doctor has come into conflict with the Daleks. Since the rebirth of the series in the noughties, the Daleks have been in near enough every series, challenging the Doctor. They have made the most number of appearances overall, the only other adversary that has come anywhere near that are the Cybermen and the Master. Unlike the Cybermen and the Master, Daleks are held in higher esteem, unless of course you belong to Cybermen Appreciation Society.
In the old days of fighting the Daleks, it was easy to avoid being killed by their attenae, you just ran up the stairs. Since the episode Remembrance of the Daleks, Daleks have overcame that problem by using rockets at the base of their kit to levitate upwards.
The Daleks have appeared in two films Starring Peter Cushing. Both films are remakes of previous episodes but updated slightly, having removed mention of Gallifrey. In the 'Five Doctors' special, the Daleks appeared alongside the Master and the Cybermen. In the 2013, fiftieth anniversary, the Daleks will appear along with the Cybermen and the Zygon in November 2013.
The Daleks home planet is Skaro which no longer exists, the Doctor tricked the Daleks into blowing up the planet by using the Hand of Omega in the episode Remembrance of the Daleks. The Daleks are able to travel back and forth in history much like the Doctor.
Daleks, the so called Alien pepper pots were once human in form but a war on their home planet between the Kaleds and the Thals resulted in the creation of the Daleks. The Daleks were created by the Kaled scientist Davros to advance the war and win.
Davros took a Kaled person and evolved it to the end of its evolutionary timeline. The end result was a Kaled who could not walk. A Dalek was without gender, it couldn't reproduced, it had to convert people into being a Dalek. The evolved Kaled was placed in the familiar Dalek shell. The only near human Kaled survivor is Davos who the Doctor has frequently met and beaten.
The Doctor was sent back in time by his fellow Timelords to when the Daleks were being created to stop them in Genesis of the Daleks but at the last moment, the Doctor had a bought of compassion and decided not to kill the Daleks that had been created. The Doctor did address the Kaled council to try to persuade them to stop Davros but when a vote was cast, the result was split. Davros ordered Daleks in to the voting hall and kill those not voting the way he did. The Daleks production continued unabatted.
The Daleks have two recognised leaders. Davros and the Supreme Dalek. The Daleks although most commonly grey in common, have appeared in different colours. They have used mind controlled humans called Robomen in the past, mostly notably in Daleks: Invasion Earth 2150AD.
Daleks have been a mainstay enemy of the Doctor since the second episode, called The Daleks. They were created by Terry Nation during the first series. The name so it has been said came from using letters of the telephone directory jumbled up with one or two letters removed, i.e. A-D, E-K, L-R, S-Z.
During the first series two-part finale to feature Amy Pond, the Daleks have teamed up with other enemies of the Doctor including the Cybermen and the Judoon. After the enemies have put the Doctor into the Pandorica, the universe starts to disappear and the Tardis goes supernova.
The entire universe has turned right up side down with everything apart from the Earth and the moon disappearing. When the Doctor became locked in the Pandorica, the Daleks turned from metal to stone. A Stone Dalek comes to life when the Pandorica opens causing problem for the Doctor and his companions including Amy Pond, Rory Williams and River Song. The Dalek is destroyed when the Auton Rory Williams shoots and blows up the Dalek.