I installed the developer version of Tiger tonight, herein are a few notes about the changes.
iChat supports JabberRendezvous is now called BonjourThere is a small metallic sound while typing, I guess that is supposed to help with the tempo. The dictionary app will get a lot of use from me, looking up words is my primary use for Sherlock. Logging in seems sluggishSafari 2.0 is slower at rendering than 1.3Safari has a nice new feature: "private browsing". Web pages are not saved in the history file and information is not collected for auto-filling formsI'm sure the dashboard will get some use, even if it is only for the calculatorTo make your RSS feed show up in Safari 2.0, you need to change the link type from 'alternative' to 'alternate'. Mail.app has a completely redesigned interface. And it didn't quite get the mail accounts imported correctly. 
