It's happy day, testing out Internet Explorer 7 to see what unexpected things it's done to webpages...
It defaults to Medium Font size instead of Smaller at last - excellent! People will stop complaining about being unable to read the text, and thousands of websites that only look good in 'smaller' will be screwed.
It defaults to Clear Type! I guess this makes sense with CRTs being displaced by LCD/Plasma.
CSS has absolute positioning enabled! Or... only in compliant mode. I had a lot of trouble kludging one layout to get round this on IE, but unfortunately I have to leave this until everyone has switched to IE7 unless someone can come up with an 'except for IE7' hack.
So far I've spotted only one positioning difference from Firefox, but it's not an important one.