I run Linux on all my dedicated servers. It's the absolute best for hosting. For browsing, it's the safest. A lot less hackers out there worried about attacking open sources. But, even I don't build a website around it. If a site of mine works in Opera, great. If not, no biggy. I've never seen any of my site stats show more then 0.5% Opera Users.
It's a shame cos' I dislike Microsoft more then anybody.