The Daleks... Long and stagey but never quite too dragging (even though the movie tells the story in 80 minutes or so - the length of three out of the seven episodes!). Gives us a good chance to see the crew developing...
Guess what, the original outline was for a six parter (you know that already, I'm sure). It's only really parts of episodes six and seven that really drag (6 is called The Ordeal. Was Terry dropping a hint?)
Yeah - of what Keys Of Marinus would be like...
Meanwhile, The Edge Of Destruction- Bit of a mix, some silliness ("we saw that in the fourth universe"), the first big line-stutters from Hartnell, yet also very mysterious and with the final burst of character creation, getting everybody properly into their moulds (except Susan, who isn't allowed to be this develeped again). In particular, the Doctor completes his transition from abductor and potential caveman-murderer to the "never cruel or cowardly" (Well, until the late 80s) bloke we all know...
With the reveal of the problem, it would actually (if compressed) make a really good Twilight Zone style anthology one-off.