Here are plots of the top 3 party vote share for most of the English seats from the general election plotted. Seats in the red zone were won by Labour, blue zone by Conservatives, and yellow zone by Lib Dems. The lighter triangle in the centre represents seats won with less than 50% of the vote, so shows the seats that will be affected by AV at a 3 party level.
I've shown English seats only, as results in Scotland and Wales distort the picture due to the additional presence of the Nationalist vote, which would require 3D to show properly. I've also filtered out constituencies where parties other than Labour, Conservatives and Lib Dems don't form the Top 3 parties to avoid a misleading picture.
The data comes from this incredibly useful spreadsheet which I come back to time and time again.
Not shown: Barking, Brighton Pavilion, Buckingham, Cornwall North, Dagenham and Rainham, Devon North, Devon West and Torridge, Thirsk and Malton.
Con: 185 over 50%, 110 under 50%.
Lab: 89 over 50%, 100 under 50%.
LD: 20 over 50%, 22 under 50%.
For comparison, here's the projected result from 2005:
Not shown: Barking, Bethnal Green and Bow, Boston and Skegness, Brighton Pavilion, Burnley, Dudley North, East Ham, Hornchurch and Upminster, Liverpool West Derby, Mansfield, Morley and Outwood, Poplar and Limehouse, Sedgefield, West Bromwich West, West Ham, Wyre Forest.
Con: 101 over 50%, 102 under 50%.
Lab: 146 over 50%, 119 under 50%.
LD: 15 over 50%, 33 under 50%.
In a future post, I'll identify zones on the 2010 chart which I see as having different dynamics at the next election.