Can someone give an explanation of the different types and ways to reset the Captivate? There's Factory Reset, GSM Reset and then the crazy Odin reset. They all seem to 'reset' in different ways, and as a new guy I'm confused.
This is a very general answer as pages could be written about proper usage and technique. I would advise you do more research after reading this.
The first 2 ways are used if you have issues with your phone. The reset will bring your phone back to default factory settings.
Odin is used inconjuction with flashing new ROM's on to your Captivate. Master Clear wipes the phone and the data. The next step/process would be to use ODIN to upload new firmware on to your phone. Think of it as a 2 step process.
Different ROM developers have suggested ways to flash your phone, ALWAYS read the complete forum and educate yourself about the processes and risks.