Did you also notice that the afternoon peak seems to have disappeared on some routes?

Forest Hill - Westminster
2010 Oyster Single fare:
£2.70 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£2.40 At all other times including public holidays.

2011 Oyster Single fare:
£2.90 Monday to Friday from 0630 to 0930.
£2.50 At all other times including public holidays.

So getting to/from Zone 1 Tube on a typical commute will cost the same (£5.40) in 2011 as 2010.

Confusingly, this does not seem to apply to Overground journeys out of London or to National Rail journeys, where the afternoon peak still applies.

2010 Oyster Single fares
Forest Hill to London Bridge [London Underground]
£2.70 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£2.40 At all other times including public holidays.

Forest Hill to London Bridge [National Rail]
£2.60 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£2.00 At all other times including public holidays.

Forest Hill to West Croydon
£2.20 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£1.30 At all other times including public holidays.

2011 Oyster Single fares
Forest Hill to London Bridge [London Underground]
£2.90 Monday to Friday from 0630 to 0930. [but NOT 1600 to 1900]
£2.50 At all other times including public holidays.

Forest Hill to London Bridge [National Rail]
£2.80 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£2.00 At all other times including public holidays.

Forest Hill to West Croydon
£2.20 Monday to Friday from 0630 to 0930 and from 1600 to 1900.
£1.40 At all other times including public holidays.