Mind you you did want to stick with your Humbrols and there are very few reasons why not, just thin them either with Humbrols own thinner or bog standard white spirit.
You might find, like me that you actualy like spraying Enamels.
Paul
If you must change then Vallejo Model Air paints are the only ones that I know of that don't need thinning, you just pay a lot for thinner that is already in the pot, so you get less paint for your money.
Or you could stick with enamels and switch to xtracolor, I find most of them are thin enough to spray from the pot.
Paul