He may have only had ownership of the TARDIS for one series but I thought Christopher Eccleston's Doctor was great, and never better than in this smart and heartfelt episode.
It's a simple "what happens if you alter something in time?" premise, but the performances given by Shaun Digwell and Billie Piper elevate it to being so much more.
For his part Eccleston may not have to carry the drama, but everything he does say, every little facial expression speaks volumes.
Since these early 'new who' episodes the show has got increasingly complicated, over dramatic and dull. These early series episodes were accessible and enjoyable.
I think this was one of the best episodes from his one series as the Doctor.