Ive been working on Cs4 the last couple weeks now. Some of my new favorite features are the improved auto align/auto blend features, adjustments panel and faster more intuitive pallet arrangement. I also enjoy the new way that there are more ways to customize your preferences. 

As far as bridge is concerned the photo downloader is a useful little feature if you are not using the Capture 1 4.7 downloader. It organizes the photos by date in the folder of your choice and can rename as well. What is interesting is that it will copy the files to a back up disk while downloading. This probably something you should be doing while using a all card workflow anyway in case your primary capture drive is on its way out. One thing also to keep in mind is that the card reader and external backup should be on different busses ie: one on firewire and one usb or you will be slowing down your bandwidth and creating a bottleneck. Of course its always good to check that the files are not corrupted in anyway before giving the cards back to the photographer or assistant for format. While Im at it ill tell you a good way to tell whether your cards are downloaded or not: face down- not downloaded, face up or logo up- card is ready to shoot. This is a industry standard just like the with the old roll film backs.

The last 3 simple things I like about the new bridge is that it will start up at log in if you want it to, it seems faster to generate previews and the overall visual interface is improved and simplified. 

Bravo Adobe!