Why won't Google Reader load in Safari 5.1.4?
Had the same problem. Tried resetting cache, making sure latest Flash was installed, turning off all extensions, etc. Turns out changing Safari to 64-bit mode was what did it this time. Open Finder, Applications/Safari, "right-click" Get info (or command + "i"), uncheck "Open in 32 bit", restart Safari. Hope that helps!

After the fact: Apple released Safari 5.1.5 this afternoon. The update addresses this 32-bit issue specifically.