What is pink noise?

So if you were going to measure in-room frequency response, would you use white noise or pink noise?
And how do you measure sound at any particular frequency? Rat Shack SPL meter and Stereophile test tones miss a large part of the frequency spectrum. I would think using white or pink noise would be much more accurate - IF it can be done.

Thanks Alcides, this sounds too expensive / complicated for me. The more I get into this stereo stuff the more I realize it's practically impossible to figure it out - at least for me.
Anyhow I think I'll be getting a Tenma SPL meter, $119 from mcmelectronics and Rives Audio test cd. The Tenma is +/- 1.5 dB and hopefully better that Rat Shack.