I agree with go with what you like, but if you feel color challenged there are two tricks that might help...
1. Buy the all the fabric for a quilt from one fabric line. After all the manufacturer do make an effort to coordinate the look, so take advantage of it. This where charm packs/layer cakes/fat quarter packs/ etc. come in handy.
2. Another trick is a trip to the paint store-- yep the paint store. Those free paint chip brochures have wonderful professionally coordinated color combinations. Pick up a few of those and march off to the fabric store and let those guide your fabric purchases.
I am sure others will chime in with some of the tricks they use to pick fabric.