I used Tamiya paints for years to paint figures. Its only the last 3 or so that I've used the Andrea/Vallejo colors for figure work. Since I do mostly figures these for me were worth "tooling up" for and stocking a large selection of colors. I would not reccomend the model color line of vallejo for vehicle painting unless you're brush painting. They don't do well in an airbrush because of the pigment level (higher) that causes blocking and necessitates frequent cleaning. If you are into the Vallejo line I'd go for the Model Air line as they are formulated for passing through an airbrush. Tamiya or Model Master are excellent vehicle paints and are more readily availaible through hobby shops should you run short and don't want to wait for mailorder.
I use primarily three skin colors from Vallejo. Dark flesh, flat flesh and light flesh. Any more highlighting or shading I use reds, browns, or white to get a wider range of tones. Everything else is for uniforms and equipment. Since I do a variety of periods I have a large collection of colors. A little research into color and finding a color wheel will help you in keeping your paint stocks down and your wallet heavier. No need to buy 3 colors of red to make highlights and shadows. White mixed in for cooler highlights, yellow fmixed in for warmer highlights, green, blue or brown mixed in for shading will give you an almost infinite variety of tonal variation. This way as you build your color pallets, you can get the most out of the least amount of colors.
Its better to buy your colors individual at first rather than as sets. It may be a tad more expensive but you get exactly what you want. Rather than 7 flesh colors, black and white when you really only need three.
Like any resource and "tool" you'll get alot of advice over what is better and what works for each person. Experimenting is the best course and you'll eventually build up a pallet of colors that mix brands that work for your genre of modeling. I use Tamiya, valejo, andrea, Model Master for different applications and as a result of personal likes and characteristics that appeal to me of the various products in my paint drawer.
Good luck.
Mike
"Imagination is the dye that colors our lives"
Marcus Aurellius
A good friend will come and bail you out of jail...but, a true friend will be sitting next to you saying, "Damn...that was fun!"