If you're anything like me, and you like using video authoring and graphics tools (Pinnacle, Photoshop) or web dev IDEs, you are likely to end up with a lot of fonts. Usually my Windows installation hovers at around 800-900 fonts, and the system performance hit is considerable. I've actually never looked into removing fonts, my approach has just been to avoid installing ones I did not want, but of course with Windows' default selection of fonts that's not an option. I honestly don't know why they always slap those Arabic etc fonts in there, when I am willing to bet that 99% of users of North American editions of Windows never have any use for them. Localized versions for the Middle East would be another matter, of course.
Adding a lot of fonts into Windows does most definitely adversely affect the system's responsiveness, particularly when using apps which load them up, such as word processors, or graphics tools.
I've never looked into it, but I wonder if those Arabic etc fonts are in the Windows/Fonts directory as regular .ttf files...if so, could they just be manually removed? I'm not logged into Windows right now or I'd check myself... Keep me posted please, I wouldn't mind an answer to this question myself, for future reference.