The Williams are sorta heavy.
You should be able to get use HED Stinger 6s for under $800/pair. I just peeked on eBay. A slew of Reynolds wheels, 46 and 66mm, for under $800. If I were using normal/narrow rims I'd be all over the 66s at $650. Not so many Stingers but if you get a 2009? or later Stinger then you'll definitely want to have wide clinchers for training, else you'll be redoing your brakes every time you switch wheels. I'm a fan of HEDs and Reynolds. Zipp I suppose but I haven't owned or ridden any of their recent wheels, like since they started making the 404s (I had 340s and 440s).
__________________
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson