With IE9 beta (UA: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Tablet PC 2.0; .NET4.0C; .NET4.0E; InfoPath.3; Zune 4.7)), the site layout is wrong (unusable) whether compatibility mode is enabled or not. You can see in screenshot 1 that with compatibility enabled, collapsed slash boxes do not expand properly. In screenshot 2 with compatibility disabled, the "more" button at the bottom is in the wrong place. In this mode, there's a few other layout problems around the page but this is the most pronounced.
Screenshot 1
Screenshot 2