Been awhile since I’ve lurked on the forums!
One thing overlooked here is the impact the room or playback space will have on any monitor system. Usually, the room used for playback has a much more significant impact on the sound than any monitor speaker has. Many smaller rooms create major problems for bass and mid range playback, as the physical dimensions ofttimes accentuate frequency resonances in the worst possible ranges. If you’ve got a budget for really good monitors, also think about installing some worthwhile room treatments, if you are creating a dedicated space for production.
A dead space is useful in that it won’t color the sound much, and will make post-production a bit easier, as you can actually “add the space” back into the final mix with various tools from reverb to EQ.
Even if you don’t have a grand budget, you can usually use blankets and other thick foam to deaden or damp a room and it’s resonances, including creating gobos and bass traps.
A significant caveat: don’t smoke, block vents, or otherwise use flammable materials in ways that can make your studio into a fire trap!
There are numerous materials available that are fire retardent that will very effectively do the job. But they’re usually a bit more pricey, again depending on budget.
Finally, rarely are two listening venues are the same. So if you’re producing for radio, you might try a rough mix, and then listen to it on a number of playback sources from iPods to boomboxes to car radios to a full blown hi-fi system to ensure that it comes across reasonably well for ALL these various modes of playback.
Hope this proves helpful!