Just a small correction to some of the above......
"However, (now the bad news) version 5.5 of ACR only works with Elements version 7 - not version 6 as you have."
Not actually true..... ACR 5.6 (and 5.5) will work quite happily with PS Elements 6. It's ACR5.7 that will not. Fair mistake, though, as Adobe seem to get themselves screwed up with this and are currently still saying what Forseti states. And I have more and more difficulty even getting on their website.
I'm rather glad that my camera gives me the choice of DNG as well as the camera's own Raw version.