Noise reduction on separate channels can be useful if you have noise concentrated on one particular channel (my 20D under tungsten light at high ISOs often has a totally shot red channel for example). So far I prefer to use the ACR noise reduction at lower ISOs, if necessary and the more agressive Noise Ninja for high ISOs, than the new noise reduction filter - the latter's strength seems to be chroma noise rather than luminance noise reduction and I have used it on some P&S files with a deal of succes a couple of times - the chroma noise on my 20D files after ACR processing is pretty much zero anyway.
Other features (my own personal view of the things I've tried): Smart sharpen is worth playing with, especially using motion blur for pictures suffering from camera shake - but for many images, if you know what you are doing in USM the latter seems to give a an equally good result with less messsing about to get the right settings. The lens correction filter puts a few third party offering out of business - if you don't already have one it saves $50 or so there - works really well.(I'm on MacOSX so there isn't a free version that I'm aware of out there) And I like the way on these new filters that you can save presets in a drop down menu, without having to go hunting to find where you saved them.
Raw handling is improved - and for some cameras there may be less obvious under the hood improvements (eg the 20D processing has improved a little in regard to pattern noise at high ISOs).
Spot healing brush is pretty cool, as is the red eye removal (about time too!)
If you are into compositin gat all, smart objects and the new ability to warp stuff makes it sooooo much easier (look at the example on the NAPP video of wrapping a label round a can.) Useful and fun too. I haven't played with the perspective tool yet - not something I'd use on a regular basis but I can see where it would make tasks that are otherwise complicated much harder.
I like Bridge. I really like the way I can automate standard conversions and batch resizings without having to write an action to do so. I've still got to work out the full workflow implications, but in principle I think it gives a lot more workflow options than file browser did.
I have no idea what the shape blur filter is intended for - but the "right' choice of starting shape can produce some interesting effects..
Best thing is that it runs no slower (and if anything slightly faster) than CS did. And I'm using a 600Mhz G3 imac with less than 1Gb of RAM... if that can run it enyhting will!
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Some of the least worse of my photos:
http://www.flickr.com/photos/susans/ 
