I'm having a very similar issue except that it's not related to my SD card, and I'm desperate to find a solution. This phone used to be like my best friend, but every since the Gingerbread "upgrade," I spend an increasing amount of time fighting the temptation to throw it in the trash. I've been waiting for the Bionic for almost a year and I'm hoping to either find an answer before then since I feel like I just can't take this for another month even if it is released in August.
My crashes aren't occasional. I've had them happen as often as 18 times per day, and always when I'm listening to audio,and it's not related to the application. It happens with the stock player, Audible, TuneIn, and Pandora. The phone just suddenly shuts down and it's often next to impossible to get it to restart. I've cleared the system cache and removed almost every app that insists on running in the background, other than Lookout and the stupid stuff Verizon doesn't let you remove.
I'd be very grateful for any help. Audio is about 70% of what I use the phone for since I listen to streaming radio all day at work. I'd be willing to do a factory reset and go through the irritation of reinstalling and reconfiguring all my apps if I could find any evidence that would resolve the problem, but all the posts I've seen from people who have tried that say it didn't make any difference 