I find myself using the same color palette over and over again. I'm always using Golden paint's Quinacridone Nickel Azo Gold, Transparent Red Oxide, Dioxazine Purple, Turquoise Phthalo, Quinacridone Magenta.
My newest favorite (also Golden) is Green Gold. I've just started exploring the possibilities with this color. Maybe this will help me get out of my color rut.
Tip: Bookmark this page for help with color.
colorschemedesigner.com This site is very helpful for figuring out color combinations including analogous colors, complimentary colors, split compliments, etc. It also shows tints and shades of the primary hue.