I stopped using v2007 because it always ran in the background even though it didn't even have realtime protection. Does 2008 do the same thing or did it get back the normal days of v6?

When Ad Aware and Ad Watch are both closed, the only Ad Aware related process running in the background is aawservice.exe
This is the core service which needs to be loaded at windows startup in order for Ad Aware to function properly and since it has a very low memory usage at Idle times, it shall not be a big concern.

Regards,
Laleh