I'm going to completely disagree with the routes above and suggest
going for the Piccadilly from Earl's Court, as it's much more frequent
and faster than the Circle and District lines. The change at
Paddington also means that the topic starter cannot take any
Hammersmith and City line trains, even though they may very well
provide a faster journey than waiting for a circle line train at
Paddington.

Every day I have the choice of taking either the District line or the
Northern Line + NR for my commute, and every time I've gone for the
District I've regretted it. It's just so horribly slow, infrequent and
prone to delays.
I'd even consider just walking from Stamford Bridge to Earl's Court to
avoid the District altogether.