Would it be a dumb idea to have two different size/style monitors setup? I'm currently using my new Samsung 22", but now my old 17" Apple display is on the floor gathering dust. I know it wouldn't look great but would it be something do-able? I'm using a Mac G5 if that makes any difference.
It's fine. I have my laptop connected with my desktop's monitor. Laptop screen + desktop monitor = ghetto dual monitor. It won't be as pretty as 2 same size monitor. But it's definitely better than a single one.
You can park static stuff in the smaller monitor, like email. That way you can see it at a glance as opposed to having to move windows around.