So I was trying to debug on of our Sites because we we were having an odd sign at the beginning of the files.
Turns out it was a BOM at a database model somewhere totally different from the output phtml. If you got any windows developers using Ultraedit in your team give them a hearty punch from me. :-)
But since I didn’t know where it was from and what it is at the time I opened the result in a hexeditor and searched for the beginning(for the record, Wikipedia has a list of the different UTF BOM’s but most editors hide them):
grep -r `perl -e 'print "\xef\xbb\xbf"'` *