ATI released their newest set of Catalyst drivers, which brings the improvements listed below. You can read through the entire changelog (PDF) if you want more in-depth information. Also, be aware that there is a hotfix released for the HD2000 and HD3000 series, which you can download along with the drivers below.
Crysis DirectX 10 performance gain up to 20%
Crysis Warhead DirectX 10 performance gain up to 20%
World in Conflict gains up to 5%
There are also multiple bugs resolved, both in the CCC (Catalyst Control Center) and in various games like Call of Duty 4.