Don't laugh. But I like to use regular bath hand towels. Nice colors, weight, etc. I like the ones Wal-Mart has.
http://allaboutblanks.com/
Try All About Blanks. They have a great selection of linens of all kinds.
Marcelle
http://embroideryavenue.com/
http://embroidery.gotop100.com/
Where I live I like to go to BIG LOTS I can get them for $1.00 each. I too like the waffle tpye.
I get mine from Walmart. I use mainly the waffle type. I believe the ones that already have some color trim to them would work nicely too.