This sounds like the opposite issue that you have, but when I connect my phone to my work computer via USB and enable USB storage, I get a message from Windows 7 that my SD card need to be repaired. I just hit ignore and proceed as normal. I don't seem to have any SD card issues otherwise.
My home computers (Mac and Ubuntu) don't have any issues. On my Mac, the SD card mounts automatically. On Ubuntu, I have to 'mount /dev/sdc1...', I don't use the desktop much so I don't recall how it behaves, but I don't remember having any issues.
Similar for me, Win7 wants to repair the card instead of just viewing it. XP and Ubuntu are happy. Seems like a Win7 issue not a CM7 issue.
Sent from my abucus