$400 will not be enough for what you need, if you are serious about what you need it for you will need to open your wallet a bit more.
I have heard from numerous people that high end dell displays are great however, I have the led 24" apple cinema display and it is completely flawless.
Best colour I have ever seen from a monitor ever, resolution is fantastic, HD movies look great, photo editing is fantastic (photoshop), in built speakers are awesome sound quality, looks stunning, and the other solid features that make this monitor perfect for any macbook owner, I also watch movies and eyetv on it.
It is out of anything else's league, the one big disadvantage: the price, which is pretty big, but your getting USB hug, mic, iSight, Mag safe adaptor, awesome speakers, and its killer feature, a display that destroys all others.
Is it worth the price, for me: yes, for other people it might not be their cup of tea, but this certainly makes the $600 dell monitor that my friend bought look reasonably shabby