I really like Vallejo paints. Everything I've come across is quality. Their primers are some of the best products on the market. That said, there are a LOT of colors available and there is some overlap between their paint lines. Admittedly, I'm a bit of a completest, tending toward OCD. That means I want all of the colors. All of them. To that end, I put together a list of the Vallejo paints along with some of their equivalents.
I started with this fantastic table that is intended to be a cross-reference for Citadel paints and expanded it to include the three lines of Vallejo paints. I added the paints along with swatches of their color. This shows the overlap between the different lines - Game Color, Model Color, and Model Air.
Model Color includes most of the original 72 Game Color line but does not include the newest 15-20 that have been added. Relatively, there isn't much overlap between the Model Air line and the other two. With all that said, here's a link to the spreadsheet. Since you can't normally sort a Google spreadsheet without having edit capability, I created three tabs, each sorted on a different paint line.