I have spent probably the last hour or so reading and looking at paints and all I have to show for it is a headache.
So you're new at this? I've only been doing this a few years and I'm hundreds of headaches in…
I realize there is likely no one true answer to this
The real problem is that there are
too many correct answers.

First a caveat: Never trust a color on a computer monitor or laser/inkjet printout. Modern desktop technology is notoriously inaccurate with colors. I can't even get the exact same window to be the same color when dragged between two identical monitors with the same settings sitting side-by-side and plugged into the same computer.
What I do is buy a range of the paints purported by different manufacturers to be the "correct" color for a particular standard color, then either:
- choose the one that looks best at the scale I'm painting, or;
- use them as a reference to get an end result that looks about right.
Many of the "correct" colors just look too dark on small scale miniatures. They might look great on the large surfaces of 1/72 aircraft, 1/48 tanks, or 1/700 ships, but I'm usually painting 1/200 to 1/300 scale aircraft or tanks, 1/1200 to 1/2400 ships, etc. so I need to find paints that give the right impression but are actually shades lighter. Many Vallejo colors look too bright and cartoonish straight out of the jar, but sometimes an overbright Vallejo color is the right hue for a particularly small model, or as a basecoat that will be darkened with a wash.
Some paints just don't go on well, no matter how correct they look in the jar. I have a growing collection of "correct" paints with poor coverage that are basically just paint chips to guide me.
I also have a growing collection of almost-close-enough colors that I prefer simply because I have a matching spraypaint and brush-on paint. It saves time and preserves detail to be able to coat the entire model in a close-enough basecoat, pick out the details and cammo pattern(s) in different colors, then fix mistakes with a brush-on touchup that matches the spray coat. I correct not-quite-right basecoats with drybrushing, thin coats of the correct color, or washes.
Some other resources that might be helpful:
Here's an online FS 595 color server.
This page has a nice collection of color conversion charts.
This site has a button to launch an Adobe Flash color conversion chart that will let you cross-reference colors from different paint manufacturers and color standards.
- Ix