On 12 Mar 2006 10:13:14 -0800, "MIG"
wrote:

Many years ago, off peak Metropolitan trains all terminated at Baker
Street. In the peaks, trains from Chesham terminated at Moorgate,
trains from Amersham terminated at Liverpool Street (platform now
covered in offices) and trains from Uxbridge and Watford terminated at
Aldgate.

Is there a similar fixed pattern nowadays in the peaks,

There is off-peak, but not during the peaks - trains to/from any of
the four branches can start/terminate at either Baker Street or
Aldgate. Another thing that's variable (I think) is what stations
trains to/from Watford stop at between Harrow-on-the-Hill and Finchley
Road (either all, none, or just Wembley Park).

or do a whole variety of services terminate at Moorgate?

Trains are rarely scheduled to terminate at Moorgate nowadays - it's
unpopular as trains terminating there have to cross the westbound
track. It's mostly used for turning back late running trains heading
towards Aldgate to bring them back on time.