I know it's legal to have roms of games you ownActually that's borderline, making a copy violates the DMCA, they shouldn't really exist, even (as Rockstar just said). Ever notice how sites like acekard list "updates" via the release number (a non-official ID) instead of using any game titles?
EDIT: If you trade the game away you need to destroy your ROM copy, and if you're to play your ROM then you need to destroy your real copy, as the ROM is JUST for backup, two functional copies shouldn't exist since you only paid for one.
http://www.copyright.gov/help/faq/faq-digital.html#backup
QUOTE said:
Under section 117, you or someone you authorize may make a copy of an original computer program if:
* the new copy is being made for archival (i.e., backup) purposes only;
* you are the legal owner of the copy; and
* any copy made for archival purposes is either destroyed, or transferred with the original copy, once the original copy is sold, given away, or otherwise transferred.
QUOTE
It is also important to check the terms of sale or license agreement of the original copy of software in case any special conditions have been put in place by the copyright owner that might affect your ability or right under section 117 to make a backup copy.