For one thing, the general purpose computing on graphics processor chips (GPGPU for short) could very well melt your entire face off into a puddle of pathetic all over your razor thing Apple keyboard.
For another thing, there's this 64-bit business. Bandied about by marketing types for years, the tech is legit in Snow Leopard, and we explain why you should give a hoot in our lovable Giz Explains series.
Also on the cool front is this confirmed feature regarding the front-end. Basically, with Snow Leopard the HFS+ drivers will let you access a Mac's files from Windows while in Boot Camp. Multiple OS's? Totally seamless.
Sort of confirmed, sort of up on the air (but going strong): MacBook 3G support is built into Snow Leopard.
Oh, and screen recording is making a triumphant return with Snow Leopard's Quicktime Player.
Of course, questions become answers when WWDC '09 begins in earnest tomorrow.