Amazeelabs.com is amazingly fun and illustrative. The site makes extensive use of PNGs to place their artwork and icons. The effect is open and fun. The site is well structured and easy to navigate. I especially like the newsletter, which is a drawer at the top of the contact page. It’s a nice effect. The illustration on this site has a really great personality.
The site was designed by Mike Kus, if you haven’t found his work in the wild yet, go check him out.