definately worth it for parts, probably worth it to fix RROD and use for 3-6mths. Might not be worth it at all if you don't like to mess around when it comes to gaming, personally knowing that RROD can return at any moment is like a sickness that plagues me, thinking about it all the time when playing.
If done right you should be able to get $80-$100 by parting it out in Buy/Sell/Trade forums. $40 for DVD, $20 for PSU, $5 for cables, $15 for MoBo, $15 for case, heatsinks, ect.
Just remember RROD almost always comes back to haunt you in the end, so if you fix it and sell it, expect the buyer to come back with RROD unless you are up front about it and only garuntee use for like 2mths or 3mths. Just use your head if you sell it, $60 for console that last 3 months... meh. $160 for console that lasts 3 months....