Personally, I would stay away from Android 4.0x, if you flash, root your phone & do a factory reset, the brickbug comes into play (4.0.4). There has also been one or two people who didn't even root their phones (allegedly) who bricked them doing a factory reset on 4.0.4.
If you must flash 4.0x, use 4.0.2/4.0.3 (I still wouldn't even do that). If you have problems with the flash, for example, bootloop - boot into recovery & do a factory reset. If that doesn't fix it, find Hopper8's 'Odin troubleshooting' thread stickied in General, download the 3 part firmware linked in the thread, and flash that with Odin (this will wipe your phone).
If you still can't get a successful flash, it might be something else fairly simple as is often the case with these, try everything in Hopper's thread. I'd be surprised if you can get a successful flash with the info in his thread, it's 'the Bible' for these things.
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?