According to the bombcast comments some people are able to use the feed at http://www.giantbomb.com/podcast-xml/giant-bombcast/ while others aren't.
Loading it in firefox shows a blank feed but it does have the usual options at the top, and if you look at view source it seems to all be there.
On a hunch I checked it with http://validator.w3.org/feed/ and it says that "’" is not a valid entity. It *is* for HTML but apparently not for the XML defining podcasts.
According to http://www.apple.com/ca/itunes/podcasts/specs.html#commonmistakes, the only entities supported are "&", "<", ">", "'" and """. They suggest leveraging UTF-8 to output other characters (like accented characters) directly. I guess that some feed aggregators kindly accept HTML entities in their XML, but it definitely seems like iTunes does not. Hopefully this is not a difficult change to make in the back-end...
Fixing this might also fix the podcast on the iTunes website (I don't know how it is arranged though, so that may not be true).