there really are no big hacks for vB as of yet. the only one that isn't a standard part of the program is the Active Topics list, which can be found here.

99% of the things that had to be hacked into UBB are standard on this proggie, so there isn't much need for a hack. Things that are hacked here are generally going to be added to future releases with toggles for those who don't want them on their boards.

As far as ease of hacking, PHP is easier than Perl...