I switched my site's main category menu to blend in better with my 728x15 Adlink. I'm trying real hard to increase my low CTR%. Please take a look and tell me what you think thanks! www.evilpsp.com
Only time will truly tell if your CTR increases, but I would not be inclined to click on the ads in the header such as they are.
It can be hard to get clicks for ads in a header, alot of people are blind to them just because it's been done so much.