You could use Opera in RSS mode. Of course it won't tell you how your website will look on all browsers and all devices, but at least it'll give you an idea. Opera is available for Windows, Mac OS X, Linux, FreeBSD, Solaris, Nintendo Wii, Nintendo DS and cellphones.
With Opera you can also easily see if your website is usable without images and/or without CSS, using toggle buttons to enable/disabled CSS and images.
A good website should still be usable without plug-ins, javascript, images and CSS. If you can't navigate or read the website content with all of these disabled, then something is wrong.
Ooh, that Opera Mini simulator is really nice. I'd wondered what my site would look like on a phone, and it turns out not bad at all--I like how that browser automatically collapses menus to make scrolling past them easier. Yet another browser that I can test in.