The thing with monitors as a general rule --> Buy the most expensive ones you can afford! <--
However, the best thing to do is rock on down to the your local and test out as many as you can. Take your lappy, or a cd containing a bunch of YOUR songs. This way you'll be totally familiar with the sound and you can see how the speakers respond. You want speakers that are going to respond to all frequencies the same way (a flat response) and most good monitors will come with a frequency response chart for each speaker (e.g. pic below - although this isn't from a monitor speaker, it has a typical response curve for them from around 50Hz to 20,000Hz). You want this chart to be as smooth as possible with no booming at certain freqs.
Monitors are only as good as your understanding of how they respond to certain things. You kind of have to kearn how to listen to them. OK, as for the "which monitors" question, I'm not totally familiar with the ones you listed above, but do check out the new Tannoys Reveal series -->
HERE. I hear they are the shiznit my friend.
B
