Try deleting Safari's preferences file. Go to your home folder, then Library, then Preferences. Drag com.apple.Safari.plist to the trash can and open Safari.
By the way, whenever you experience the "Spinning beachball of death" you can almost always recover without powering the Mac off. Just hit Command, Option, Esc and the force quit dialog should come up and you can select Safari and hit force quit. You can also hold down Command, Option, Shift, Esc for a few seconds, and it should just autoforcequit the foreground program.
But how do you close the offending webpage without having to shut Safari down completely? If only one page is mucking things up, I don't want to lose everything else I am working on on separate pages. (When I still computed on the Dark Side, I could hit Cnt/Alt/Del and have the choice of WHICH webpage I wanted to close)
Also, when you do a hard power off, you more than likely have now more problems with the disk directory.
You would have needed to do CHKDSK to fix that problem.
While in Safari, or not, delete the temp and cache files and folders used, there are at least three:
Booting from OS X DVD and choose Utilty menu and Disk utility, repair your drive.
/Users/account/Library/Caches - Safari, metadata safari, com.apple.safari etc