With regards to where to draw the line with website widths; [link] (looks crap with RO browsers - so crap you won't be able to see what I'm getting at - it uses lots of CSS) really needs a minimum of 800px. That's mainly for the logo, though, and I'm not too happy with it being 800 - 600 would be a lot better. And I could add some CSS rules for other media (TV/PDA/etc) that could rearrange the design to be even smaller, and therefore work on those devices. I'm going to do all that after Christmas.
I think there tends to be a "it's too tricky/I don't know how/it's easier doing it like this" attitude towards websites. Just think though - cutting corners when designing your website is exactly like cutting corners programming - it'll get you into trouble somewhere down the line.