Mercedes - Silver (sponsored and unsponsored)
Porsche - Various liveries but an underlying white theme
Toyota - Primarily red with white trims
BMW - White
Audi - Silver Silver Silver
Bentley - Green
MG - Green and Black
Cadillac - Silvers and blacks
Dodge - Red (Reynard-Chrsyler was also red, though the Dallara-Chrsyler became a sort of blue and silver)
Just browsing various Maserati world sites there seems to be an underlying blue, but maybe thats just the webmasters fav

Also, anyone know Maserati technical partners? What kind of tires do Maserati's come out of the factory with, what brand of radios, who makes their semi-conductors. I think they recommend AGIP lubricants.
Should be good to see them back though the teams they are rumoured to be with arent absolutely top, then again we cant expect them to send Ferrari F1 personel over