A while back I've read a topic about this Acclaim MMO, Spellborn. When I checked a video about it the first thing that came to my mind is that I heard the sound from Holy Fire during the video. The video can be found here:
It starts around 13 sec.
Now I'm checking this other game 9Dragons also by Acclaim and I can hear atleast 3 sounds used in WoW. Here's the vid:
The very first sound sounds alot like the "Discovered <insert map area> xx exp. gained".
Then roughly around 10 seconds when storm vs. storm fades in I can hear a clear mage armor sound buff.
Third sound comes in at about 15 seconds, you useally hear this when you apply Sacred Shield on a target.
Is this a coincedence I can spot so many or is it just me?