I don't use a mouse most of the time, because I have tendonitis in my forearms and find that I can use a keyboard for a whole working week without too much pain, whereas any mouse usage starts hurting badly in a day and half. As a web developer, I spend a lot of time with the Internet, developing on it, networking with it, reading on it, and so on - and I do it all without a mouse.
Keyboard Shortcuts
With all of these put together, I can do pretty much everything.
Accessibility
The upshot of this is that I consider myself to have "accessibility requirements". I don't use a mouse, so I can't click or mouseover. I use dropdown boxes by focussing and then arrowing down - so if yours triggers stuff at onchange, then I probably can't use your site. I have javascript turned on most of the time, but plugins turned off (I can't click on anything anyway) - and I regularly use Opera's shortcuts for enabling/disabling CSS and images (ctrl+g and ctrl+i respectively) if I can't see what's going on. Opera also saves my preferences per site - so I can fiddle with settings for scripting and plugins on a per-site basis which is really helpful.
So there we go, if you have RSI problems, try using the 'net from your keyboard. And if you thought "accessibility" went with "disabled", think again.