I found that by the process of elimination that removing all the pictures I took using Camera 360 from my device that all my pictures appeared in Gallery (plus local music showed up in Apollo).
I started thinking it was a file name length issue so I renamed quite a few photos from the C360_* naming to the IMG_* naming convention and was able to see some of the photos taken from Camera 360 but there were still some that cased the media scanner to fail. After reviewing the properties of the photos that were still causing the issue the only thing different was how Camera 360 stored the GPS info. Next I stripped that information from the photo and finally was able to get all my photos to appear in Gallery.
Still I feel there is some sort of issue with media scan since this wasn't an issue on CM9 and earlier but I'm happy to have made progress on CM10.
Hope this helps, if not perhaps when you get time try the process of elimination method to see if you can find something common breaking media scan.
Hey lnxfrk, thanks for the reply. Yup it works! Boggles me why this is the case, but I just deleted all the snaps taken by Camera360 and its working, just like "Butter"
Running the latest CM10 nightly based on 4.1.2 and I'm just lovin it