For full sun consider Hydrangea paniculata 'Limelight'.
A good shrub for sun is American beautyberry: Callicarpa americana; it gets pretty large and has colorful fall berries.

Thanks esh, I looked at the American Beautyberry and it looks great - tolerant of poor soil, drought resistant, hardy like a weed - maybe I won't kill it! I have a long stretch of driveway with an embankment on one side that I need to plant something on ASAP so I won't lose the slope to erosion - I think the Beautyberry with vinca underneath as a groundcover to help keep the weeds out might be exactly what I need. I like the limelight, too - I want something flowery near the screened porch, just wasn't sure a hydrangea could tolerate full sun.