I ran across this list on the IEBlog while searching for...ahem, cough, uh, a hack. Microsoft offers this "list of common CSS hacks" and says these are the bugs they're ridding the world of in IE7 and that will soon break any pages you've used them on...
They were troubled times--times of strife and turmoil, man against man, browser against browser. Into this chaos of lawlessness, brutality and disregard for web standards, stepped a new contender. Sleek and powerful in a case of shining armor, the champion strode onto the field of battle bearing a new and mighty weapon that made strong Windows men quake and PC women swoon. Parallel, he called it, and fascinated, the people flocked to him... After over 10 years of staunchly defending the ruling party, I am switching sides. Yes, that's right. I'm going over to the macrebels. Don't bother to try to talk me out of it. It's no use. Call me a traitor. Tell me I've been seduced by a handsome case and dubious technology. I've heard it all. My mind's made up. I've put in my order.