I have to agree, "Start at Christopher Eccleston (number 9) and work your way up to Matt Smith (11 and current)"
I started when Season 5 (Matt Smith's first) was just starting, so I watched season 5 and 6 as they came out.
Then I found on one of those sale-a-day web sites, seasons 1 - 6 (all six seasons) for $65.00. I then watched seasons 1-4 in order and I have to tell you it is absolutely one of the best EVER experiences I think have ever been put on television.
So (and I'm not crazy about Eccleston but it introduces Rose who I love) do yourself a favor and spend a few weeks and go seasons 1-6 (episodes in order) and give yourself a real treat.
Edit: the number gets confusing. The 1-6 cover from 2005 - current.
Doctor 9 = Eccleston (Season 1)
Doctor 10 = Tennant (Bartie Crouch Jr. from Harry Potter, by the way) (Seasons 2,3,4)
Doctor 11 = Matt Smith (Seasons 5 and 6).
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http://www.youtube.com/watch?v=BRdHJAX4S_w
^^ Bloody Blackberry (original song/video)
http://www.youtube.com/watch?v=q7khBUbMHVQ
^^^ "She Used to be a MILF, Now She's a Zombie" (my best original Youtube vid. Song was fun to make)