M-Audio is hard to beat in that price range. I haven't heard those monitors, so I can't speak of them directly. You'd probably want to add a subwoofer to them eventually because of their small speakers.
These are some nice headphones. Closed back.
http://www.musiciansfriend.com/srs7/g=rec/search/detail/base_pid/244501/
Mixer wise, I can't really comment. I don't use a mixer in my set up.
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