Blanket Needs a Border

My sock yarn blanket is patiently waiting for me to knit the border so that I can call it done.  I've really enjoyed making the afghan.  It may seem like a lot of work, and it is, but knitting all those little diamonds and triangles has been relaxing.  It's been fun to see how the blanket was evolving as I added blocks of random colors.  I had no idea how the finished afghan would look.  I still don't, and won't, until I knit the border.

All the ends are woven in except on the edges.  I'll leave those until the border is done in case they are needed to close up any small gaps. 

Now is the time to make a decision about the border.  I've already decided that I'll do it in garter stitch, working one side at a time, increasing on the ends on every other row to make mitered corners.  I've ruled out using a striping yarn as I'd like each of the four sides to match and I don't want to try to make each of the sides line up.  It would be particularly difficult since there will be so many stitches.  I've pretty-much ruled out a solid yarn. After knitting with so many colors I'm not ready for miles and miles of just one color.  I want to keep the color momentum going.  I guess that leaves a variegated yarn, but what would be a good central color?  I'm thinking of burgundies or blues.  It's time to go and check out the stash and see what I have on hand.