In message . com, sb
writes
I prefer the view from Waterloo Bridge which is one of my favourite
London views.

The Kinks thought this as well.

"Waterloo Sunset" happens to be my favourite song of all time.

I suppose to answer the OP's question, we really need to know if s/he
means the most scenic as being "beautiful" or "interesting". For the
former, I really do love the outer sections of the Met. To my regret
I've not done the Chesham branch. Must put that right one day.

For "interesting" I'd put the suburban splendour of the outer bits of
the Piccadilly (both ends, actually), shared Piccadilly/District
alignment and the original section of the Metropolitan.

Actually, for interest I'm more a "stations" person than a trains one,
so my list of interesting (beautiful, even) stations would have to
include:

Southgate/Oakwood/Sudbury for 30s splendour

Baker Street for design and early Underground atmosphere

Gants Hill for the "Moscow" concourse

Newbury Park for the slightly wacky bus station (if it's still there?)

Maida Vale for the best bit of Leslie Green design not by Leslie Green

Westminster and Canary Wharf to show that London Underground today can -
when it tries - follow in the Holden/Pick tradition.

I'm sure there are other excellent ones I've missed!
--
Ian Jelf, MITG
Birmingham, UK

Registered Blue Badge Tourist Guide for London and the Heart of England
http://www.bluebadge.demon.co.uk