I avoid Javascript for all of my casual web browsing and I'm submitting this comment with w3m. So, sure, go ahead and require javascript. I won't read your site, but you probably weren't going to make any money from me anyway. I only use javascript for applications-over-the-web, like banking and company calendars. Requiring javascript is a sign you probably don't have interesting reading material anyway, so you're doing me a favor by chasing me off.

It's not ok when it doesn't really contribute any serious value to the functionality the user gets, when the thing people actually come to your site for can be done without JavaScript.