There are several different kinds of the white watch. The most popular (and most expensive) is the ceramic band white watch. They can range from $300+. Although this look is gorgeous, you better be in love if you want to spend the extra dough!
For something more affordable, try the silicone or "jelly" band. I'm a big fan of this sporty Marc Jacobs look. It's got a classic look and looks great with the silver.
Marc by Marc Jacobs 'Rock' Watch, $225
There's something about white that just makes me thing summer! Heck, even the bride can rock a watch now :)