iMovie can import the format only from the connected, self powered camera (not from the files moved from the media).
QuickTime Pro can play but not edit MPEG-2 files (additional software required).
MPEG Streamclip (free) and the $20 component from Apple can export to QuickTime formats and do basic editing.
I would be moving it from a PC to my mac, so that means it will not import it? And I don't have to have quicktime to edit it, I would possible need it to export it as a .mov
.m2ts usually comes from AVCHD, which is beyond the capabilities of MPEG Streamclip or QuickTime Pro to convert. (AFAIK)
You will most likely need a third party converter such as Voltaic HD.
If you have a supported camera and connect it directly, you do not need this, but if you have the loose files out of context, Voltaic is a good solution.