Hearing a familiar tune is a common thing in any game, especially those that have sequels, or those that have been regularly updated over long periods of time (like an MMORPG).
Remixes are common within a game franchise, but I've been noticing in Cataclysm that I've been hearing tunes that sound strikingly familiar to tunes I've heard outside the WoW 'verse and even Blizzard's works. I'm not saying Blizz ripped em off, I'm just saying they bear odd similarities to things I've heard in other places.
The first and foremost that comes to mind, is in Deepholm. I was trying to find this on youtube, but nobody has this one posted. If you go to the area where you do the Fungal Fury daily (smash the mushrooms, get the bag of miracle grow, and kill the behemoths), one of the BGM tracks that play in the background sounds pretty close (remixed, and stuff added of course) to a track in an old SNES game called Terranigma.
This track played in only a couple places in the game, but the track stands out and is quite easy to remember:
http://www.youtube.com/user/19Imperial88#p/c/268227A579F15C03/40/lnBBD3uqM0A
It is very faint in the WoW version and it doesn't have high pitched foreground 'screaming', but the deeper background 'chant' is very close to what's heard in Deepholm.
I remember hearing a couple more tracks in Cataclysm areas and I was like "hey wait, I've heard this before somewhere else...." but I don't remember where or which ones, I'll post more as I find them.
Edited, Dec 24th 2010 9:34am by Lyrailis