.....and another consideration is the recipient of the quilt if it is to be gifted: In that instance you need to consider their colour preferences, and their style. You need to consider what the quilt will be used for. For example I would not consider using a predominantly white or light shaded collection of fabrics for a quilt for my brother-in-law even though I may like those shades. A gifted quilt is made for someone with their essence and life kept in mind during the selection stage.
I actually have a massive collection of those little paint colour sample cards and I find them a great help for trying to match, compliment, or expand my colour ideas for a particular quilt. Every time my DH and I go to the local big name hardware store I nip into the paint department and grab a few more colour sample cards. I even give them to intended recipients of a quilt so they can more easily show me the colours and shades they want.