MTS

Depends on how fancy you want to get. How big you want your HST to be. If you want 9" blocks, look at any log cabin setting and you can easily reproduce it with HST (see the Jester quilt below - sorry for the lousy picture):

The coolest HST quilt I've ever seen has to be Paula Nadelstern's Puzzle Quilt. Brilliant. But I don't know if you want to deal with all that fussy cutting.
http://www.amazon.com/Puzzle-Quilts-.../dp/1571203362
Here's one using her pattern but using stripes instead of her beautiful fabrics (much easier).
http://farm2.static.flickr.com/1128/...dd5849845c.jpg
Google around and I'm sure you'll find more.

If you're working on a 16 patch block (4x4 grid), you're kind of limited to the number of different designs you can come up with.
Assuming 3"-4" HST's, blocks ending up at 12"-16", add in sashing and borders, and you've got a nice size throw quilt.

My friend runs a math/sewing club in an elementary school in NYC. Every year we do a HST project. I make the sets of HST blocks (for the 2010 quilt below, they were brights with B&W or W&B, for the 2009 brights with black/stars), and each kid (8-12) has to figure out a pattern and sew the HST's together into a block. And then I have to come up with a setting. In 2010, it was one big HST. The quilts all hang in the auditorium of the school, and the kids are so proud of them.