Xsi to T1i - worth the upgrade?

I've had the Xsi for 11 months, and like it quite a bit.
Aside from the video, which I might use from time to time, but not regularly, are the changes in the T1i worth trading in my Xsi and spending a couple of hundred dollars? Is the image quality provided by the Digic4 processor that far superior?
Also, does anyone know if any of the control keys can be reassigned? I wasn't happy to see that the metering button was replaced with the AWB button, as I use the former more than the latter. I know I could assign the SET button, but I like to keep flash compensation there.

Has anyone made this switch and have a cogent opinion?

PS- Please don't suggest the 40D or something else up the line. I have a collection of SDHC cards and the BG-E5 grip with a second battery, so I'm looking to stay compatible with my current accessories.

Thanks

I had an XSi for a week before Canon announced the T1i, so I returned it and waited.

I would not say it would be worth it to you, unless video is important. There are some differences, the video screen for one, but they're pretty close.

I would say that the upgrade would be worth it if you need/want video. Other than that feature there just isn't enough other features to warrant an upgrade.