I'm partial to marbled. I just bought some red tending towards black as a marble from Blank. I wanted something to frame a basically black and white panel that also had a few shades of red as accents and it was easier to go with a marble rather than trying to match one particular color.
this is the one I bought yesterday:
http://www.blankquilting.com/blankqu...csBlenders.php
I bought it for the dragon fabric I bought from Joann's.
http://www.etsy.com/listing/10746259...25&ga_includes[]=materials&ga_search_query=cotton+dragon+fabric&ga_search_type=all&ga_view_type=gallery