Well it also depends on if you really really like the 'extra' stuff that come with the collector's edition. Collector's edition comes with a soundtrack, making of DVD, a non-combat pet (so you can show the world that you bought the collector's edition), a Northrend mouse pad, and an art book. I personally would have enjoyed the collector's edition, but found the $70 (you got it for $65. So you got it for a bit cheaper than the retail price) just a bit much for my jobless cash flow.
But none of these extra 'cool' stuff matters, if you don't have the game. And if you could not care less about the extra stuff, it 'might' be better selling it and getting the regular edition.