I'm also hoping this price holds till release. I was going to get this with the new Ratchet game and some sort of filler for the B2G1 sale that will be going on.
On a related note, is this game meant to replace Enemy Unknown? Is there any sense in holding on to the first game or should I trade now to try and maximize profit?
Trade in or sell Enemy Unknown--Enemy Within comes with both EU and the new expansion pack, so the standalone EU will become worthless eventually.
Don't do that if you ever want to play the original EU campaign again (on consoles anyway, it's a non-issue for PC). While EW technically *does* contain the entire EU game, there's no way to play through the original campaign without the additions of the EW expansion. For example, if you just want to play the vanilla Enemy Unknown campaign, without the 'mech suits' and the energy containers and new enemies, you cannot do so on console versions of Enemy Within. If you have EW on PC then you can roll back to the vanilla EU campaign no problem.
This confused the shit out of me when I first heard about it, so I researched it fairly heavily. I've confirmed the info from 2 sources:
1) From 2K Games Community Manager Ga1Friday, on the XCOM Enemy Within FAQ @ 2kgames.com forums (LINK HERE):
Can the console version play EU separately without EW?
The base game experience of XCOM: Enemy Unknown cannot be played using the XCOM: Enemy Within Commander Edition disc. The XCOM: Enemy Within Commander Edition allows gamers to play the ultimate XCOM experience. It enables gamers to play using all previously released DLC; the Elite Soldier Pack and Slingshot Content Pack, and the Second Wave content from XCOM: Enemy Unknown, along with the additions that come with XCOM: Enemy Within.
2) On the Giant Bomb Quick Look EX for XCOM: Enemy Within (LINK HERE) Anand Gupta, the dev/project lead for the game, is asked the same question about "rolling back to the vanilla campaign" by Vinny of Giant Bomb, and confirms that you cannot do this on consoles, only on PC. [the quote is somewhere in the first 10 minutes of the video, sorry I can't watch it right now to tell you exact time]
Kind of a bummer, I was planning on selling my copy of EU to offset some of the $40 cost of the new expansion, but that's out now. Oh well, I'll just wait for a price drop on Enemy Within. Hope this info helps answer your question.