AppleScripters should re-save their AppleScript .apps in the 10.6 AppleScript Editor so they run in 64-bit mode.
I keep an app on my Finder window toolbar that simply tells Finder to empty the trash; it was so old (having been transferred from previous machines) it may have originally been a PowerPC app. It, and quite a few other AppleScript apps, run significantly faster after I re-compiled them under Snow Leopard.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090902200310110