Dont even go there....
Apple has only released the latest build (10A314) of Mac OS X 10.6 (Snow Leopard) to developers on the 1st April (ominous!!)
An exact release date for Snow Leopard has not been established , though it could be as late as September.
Stick with the OS you are currently using!
If you still use Tiger on 2007 Macs - stick with it - theses no significat reason to upgrade unless you 'really' want some Leopard features. Everyting still seems to work fine with latest Tiger & Quicktime software updates.
If you are using Leopard on 2008/9 Macs - have not seen any problems with all the latest OS & Quicktime updates.
Would recommend disabling spotlight, by placing hard drives in 'privacy' area
Users may also want to consider disabling dashboard and keyboard shortcuts, expose, etc.
Simon