Might I suggest double or reversible knitting if you wish to add color to your knitting. You are usually working with two colors; however, you only use one color for two rows. Also, it makes a nice thick fabric with no wrong sides. Knitty.com has a double knit hat pattern in their Fall '02 issue. Also, check out these websites (http://www.fuzzygalore.biz/patterns/esther.shtml) and (http://www.cs.oswego.edu/~ebozak/knit/esb-patterns/scarves-part2.html) for scarf pattern inspiration. Amy also shows the double knitting technique in the advance techniques section under "View Videos."
Intarsia may be nice to try since you are working in spots or areas of color, but be aware of the need for bobbins.
By the by Fair Isle knitting is a particular strain of stranded knitting, where usually up to five colors are used and alternated with within the project.
Good luck in your color adventures.