Lavasoft have posted Build 181 of Ad-aware 6. A fairly important revision indeed, here's some of what's new;
Speed – More comprehensive & up to 400% faster than any previous 6x release.
Smart scan mode – Improves speed even further & has been optimized to detect content at the root level enabling fast & efficient maintenance scanning.
HOSTS file scanning – Newly discovered exploit that uses HOSTS file editing to facilitate browser hijacking has been countered with this addition. Now Ad-aware has the ability to scan, backup, remove, & restore known references from your HOSTS file.