Here you can find the collection of top forum themes of the year..You can See features,view live demo and buy it in themforest market with referring urls contained in each theme title..
Here is the list:
OZONE – Premium Vanilla 2 Theme
Silicon – Premium Vanilla 2 Theme
Electron – vBulletin Forum Skin
Metro – A Theme for vBulletin 4.2 Suite
Metro Mobile – A Mobile Theme for vBulletin 4.2
Metro — A Responsive Theme for phpBB3