There's an article here
from Rick Sammon on the top 10 benefits of Photoshop CS3. If you happen to disagree, fine, but don't shoot the messenger...
Those features are very useful, but on my aging 2 GHz dual Xeon system with 2GB of RAM and running XP Pro, the CS3-Bridge 2-ACR 4 is so slow as to be nearly unusable. CS2 runs quite well on this system. Perhaps it is my setup, but it is the same as for CS2. I posted my settings on the CS3 forum, but thus far there is no relief.