Vallejo Model Air works very well, simple drop in your airbrush and go.

As well with the new re-formulated Vallejo Thinner, it is now much easier to thin the Model Color line as well, 2 parts thinner, 1 part paint, stir and spray.

As far as the sets go, Vallejo makes 8, 16 and 72 color sets. I personally don't find the sets that economical, as the paint works out to about the same price as buying the bottles individually for the most part, and you usually get at least one color or 2 that you might never use. I usually advise people to just buy the colors they want, vs buying the sets. That is of course unless you buy the 72 color packs, which come with a nice carrying case, and usually 2-3 Toray brushes. Still costs about the same as buying the paint separately, but you get a nice case and some brushes for the same price as well.

The case can be purchased separately, and is very handy, but if you can swing it...the 72 color cases are probably the best deal, and they have 2-3 different sets, I think 2 in the Model Color line and one in the Model Air line.