The Sony Movie Studio 12 product range is another that will not run in Windows XP. At the moment, this is not really an issue considering the v11 range is still available and currently a lot cheaper, although I wouldn't be surprised if the v11 range is sold out everywhere within a year or even a few months.
As far as Windows 7 compatibility goes, pretty much everything I use runs fine on Windows 7.
There are two other applications I use that while work in Windows XP, run a lot better in Windows 7. One is Raw Therapee, which is RAW conversion for digital cameras. This one needs a minimum of 4GB RAM to run properly and really struggles in Windows XP due to its 3GB limitation. Another is VUMeter 1.2, which shows a realistic looking stereo VU Meter when playing audio. The older v1.1 runs in Windows XP, but doesn't as realistic as v1.2.
One thing I do miss in Windows XP is its advanced file search feature.