Doctor Who DVDs, chronologically

The years listed on Netflix are often wrong, so it is impossible to figure out the correct order to watch them just by looking at the listings on Netflix.

Titles without links aren't available at Netflix because they haven't been released in Region 1 yet, but likely will be within the next year.

William Hartnell 1963-1966
1-4 The Beginning
5 The Keys of Marinus (January 5)
6 The Aztecs
7 The Sensorites (Blinkbox 1, 2, 3, 4, 5, 6)
10 The Dalek Invasion of Earth
11 The Rescue (July 7)
12 The Romans (July 7)
13 The Web Planet
15 The Space Museum (2010)
16 The Chase (2010)
17 The Time Meddler
14 21 24 Lost in Time (Hartnell)
27 The War Machines

There were a couple movies made in 1965/66 with Peter Cushing, but they only have a vague similarity to the TV series. Most Doctor Who fans ignore their existence.

Patrick Troughton 1966-1969
32 33 35 36 38 40 41 43 49 Lost in Time (Troughton)
37 The Tomb of the Cybermen
45 The Mind Robber
46 The Invasion
47 The Krotons (Blinkbox 1, 2, 3, 4)
48 The Seeds of Death
50 The War Games (November 3)

Jon Pertwee 1970-1974
51 Spearhead from Space
52 The Silurians
54 Inferno
57 The Claws of Axos
61 The Curse of Peladon (2010)
62 The Sea Devils
64 The Time Monster (2010)
65 The Three Doctors
66 Carnival of Monsters
67 Frontier in Space (2010)
68 Planet of the Daleks (2010)
69 The Green Death
70 The Time Warrior
73 The Monster of Peladon (2010)

Tom Baker 1974-1981
75 Robot
76 The Ark in Space
77 The Sontaran Experiment
78 Genesis of the Daleks
81 Planet of Evil
82 Pyramids of Mars
84 The Brain of Morbius
86 The Masque of Mandragora (2010)
87 The Hand of Fear
88 The Deadly Assassin (September 1)
90 The Robots of Death
91 The Talons of Weng-Chiang
92 Horror of Fang Rock
93 The Invisible Enemy
94 Image of the Fendahl (September 1)
96 Underworld (2010)
97 The Invasion of Time
98 The Ribos Operation
99 The Pirate Planet
100 The Stones of Blood
101 The Androids of Tara
102 The Power of Kroll
103 The Armageddon Factor
104 Destiny of the Daleks
105 City of Death
108 The Horns of Nimon (2010)
110 The Leisure Hive
112 Full Circle
113 State of Decay
114 Warriors' Gate
115 The Keeper of Traken
116 Logopolis

Peter Davison 1982-1984
117 Castrovalva
118 Four to Doomsday (January 6)
120 The Visitation
121 Black Orchid
122 Earthshock
123 Time-Flight
124 Arc of Infinity
126 Mawdryn Undead (November 3)
127 Terminus (November 3)
128 Enlightenment (November 3)
129 The King's Demons (2010)
130 The Five Doctors
131 Warriors of the Deep
134 Resurrection of the Daleks
135 Planet of Fire (2010)
136 The Caves of Androzani

Colin Baker 1984-1986
137 The Twin Dilemma (January 5)
138 Attack of the Cybermen (July 7)
139 Vengeance on Varos
140 The Mark of the Rani
141 The Two Doctors
142 Timelash
143 Revelation of the Daleks
144 The Mysterious Planet
145 Mindwarp
146 Terror of the Vervoids
147 The Ultimate Foe

Sylvester McCoy 1987-1989
148 Time and the Rani (2010)
150 Delta and the Bannermen (September 1)
152 Remembrance of the Daleks
156 Battlefield (original version) (feature-length version)
157 Ghost Light
158 The Curse of Fenric (original version) (feature-length version)
159 Survival

Christopher Eccleston 2005
Doctor Who: Season 1

David Tennant 2005-2009
Doctor Who: Season 2
Doctor Who: Season 3
The Infinite Quest (Animated webisodes)
Doctor Who: Season 4
Doctor Who: The Next Doctor (September 15)
Doctor Who: Planet of the Dead (July 28)
Doctor Who: The Waters of Mars (February 2)
Doctor Who: Christmas Specials (February 2)

Matt Smith 2010-?


SPINOFFS:
K-9 and Company 1981

Torchwood 2006-?
Season 1
Season 2
Children of Earth mini-series (July 28)

The Sarah Jane Adventures 2007-?
Season 1
Season 2 (November 10)

For more information I suggest the Wiki page and the official BBC site.