Gonna have to be honest with you Peter... you aren't going to find much in the way of rock 'n roll on the island. Lots and lots of typical tourist stuff, but rock 'n roll, not so much. Best take your ipod or whatever your choice is.
Radio on the island is very Caribbean oriented, with one or two channels playing something occasionally resembling rock.
Like I said, load up the ipod or whatever and hit the beach.
And just because it's called the "Hard Rock Cafe", don't expect to hear the Stones or the Who or whoever.
After all, it's still Aruba and it is the Caribbean...
Live music, or I should say, singer, sings at Cafe at the Plaza...nightly. We go grab a drink or two, kids get ice cream at Baskin Robbins and hang there and listen. Check there for music or employment