I'm looking to get some headphones to plug into my Roland Cube 20x so i won't wake my daughter when im playing at night.....i need some suggestions on some decent headphones....

DON'T tell me ipod head phones because any idiot knows that they aren't the right size....
You will need a bigger adaptor (I think thats what its called) first of all. That should be easy enough to find. Get the proper earmuff type headphones. The little earbud ones like on an iPod sound shit for playing guitar through.
Get the Skullcandy HESH headphones, they sound awesome, are comfortable and come with the adapter.
Or buy an 1/4'' - 3.5 mm adapter