So I decided to give the Doctor a try this week. My only previous Doctor Who-viewing experience was approximately a month's worth of Pertwee episodes when I was a kid and my local station ran the show on weekday afternoons for a while. That and the last few Torchwood series - liked Children of Earth very much, Miracle Day not so much.
So I tried Blink, since most sources say it's a really good episode. It was. Then Zarban recommended going to the other extreme and sampling the silliness of The Unicorn and the Wasp. So I did. Also fun.
That led directly to the library two-parter Cotterpin just mentioned, so I watched those as well just now. That was some twisted crazy stuff. But still fun.
The one impression I kept from those ancient Pertwee episodes, and which seems just as true in the four 21st century Who episodes I just watched (and Torchwood as well), is that one of the themes of Doctor Who is that the universe doesn't give a damn about anybody. Every episode seems to involve one or more random people getting royally farked by random circumstance.
Which is common in television in general, of course - every Law and Order and CSI episode starts with somebody getting murdered, for example - but something about the way Who handles it makes you really really feel bad for those poor random victims the Doctor leaves in his wake. And usually all the Doctor can do is say "yeah, I'm sorry the universe jacked you like that. Welp, gotta go." No wonder the poor guy's half-insane. Same goes for the immortal Jack Harkness from Torchwood, actually. Pretty dark stuff. I like it.
So those were all Tennant episodes obviously. I liked his semi-demented approach to the character, and the loopy sensibility of the show overall. I dunno what other Doctors might be like, maybe someday I'll give one of them a try.