It's unrealistic to listen to everything you want to try out. It's not bad to purchase as long as you are able to return them if you don't like them.
I haven't heard anything about the Monoprice's yet, but the Micca's are decent (good for the size and price), though the 42x's are a good step up. However, neither will be as good as your cans, they simply can't go that low.
Given that you are trying to do this on the cheap (looking at your list), if you want to be patient and wait for a good sale, the Pioneer SP-BS22 would be a very good bet. They typically go on sale for around $99/pr and every once in a while (probably every 2-3 months) they will go as low as $65-70/pr at various places.
If you don't mind spending a bit more, at $165/pr + shipping you can get some modded Pioneers BS22's at:
http://philharmonicaudio.com/index.html
These are very good speakers, better than pretty much anything under $200 and can hold it's own with most stuff under $400.