Rom names, which ones should i keep/delete

[Layer01]

atm i have a zillion roms. mostly made up of duplicates which are a little like this for example:
Super Mario
Super Mario [!]
Super Mario[?](1b)
Super Mario[!](2b)
Super Mario[!}(3b)
[...]
Super Mario[!](10a)
and so on and so on...(the above are made up, so i dont know if thats exactly how they look, as i dont have the rom files on the pc i'm using atm)

anyway my question is which of these can i delete and is there any program out there that can do this automatically or will it have to be manual hell 
also WHY are there so many duplicates??
this question is mainly for the console roms not MAME. so snes, nes, n64, genesis, sms, gg, GB, GBadv, etc...

[pointdablame]

http://forum.arcadecontrols.com/index.php/topic,30281.0.html

http://forum.arcadecontrols.com/index.php/topic,30646.0.html

http://tiptonware.com/goodcodes.txt

[Layer01]

ah thanks, so i should use the goodutils then. one last thing, which command(s) should i use to get the Goodxxx to filter out the many duplicats. idealy i would like just one file per game.

here is what i a guessing i should do, use the scan option, then use the inplace option??? but even that only renames them...is there no way to automate a culling of sorts, telling it to filter out all good dumps from country XXX and delete the rest?