I love that I can open Office documents so fast without even having Office installed. Click on SkyDrive, click on the document. Wait a second or two, boom, it opens! (requires internet, though)
Many games run faster on Windows 8, yey!
"Alan Wake 7 to 12 FPS more
Skyrim 6FPS more
crysis 2 10 FPS more
LA Noire 4FPs more then windows 7
Farcry 2 7FPS more then windows 7
WoW 10-15 FPS more"
As for IE10 are you talking about the desktop version or the Metro version? The Metro one is completely GPU accelerated (rather than just the page within it) so visual issues with it could be due to the preliminary nature of both vendors' Windows 8 drivers rather than something inherent to the app itself. Both vendors will probably have finalised Windows 8 drivers within a couple of months.
Desktop version. Some less-than-a-second-visible glitches when switching between tabs and slowdowns on The Verge when playing Flash videos (might be a The Verge / Flash problem).