EQ2X is a different service of EQ2.. boiled down, the game is the same, however on Extended there is a F2P option (which has many limitations) with subscription options, as well as some RMT-type options in the Marketplace. For a full comparison we have a guide explaining it: EQII Services
To be honest I didn't notice any loss of people to WoW once their latest expansion launched, and the current server merges that are close to finishing up have greatly helped server populations. Before WoW's expansion launched there were new people daily on my server (and I'm sure others) trying out and enjoying the game because WoW had gotten boring for them. Yes, EQ2 doesn't have the millions of people that WoW is said to have but there is a population and many different types of people (casuals, groupers and raiders) to play with. :)
There's so much content that it would take a very long time to run out of things to do. My main char that I've had since 2005 still goes back to work on content I missed or has been revamped since I was originally there, and still hasn't done everything for the higher level content. And that's from a solo perspective--groupers and raiders have a lot more on top of that available for them.
Currently Frostfell is going on, which is EQ2's winter holiday event, and that runs through 1/6/2011. It's once of the most-loved events of the game and there's many quests, crafting, armor upgrades and so forth to be had from it. The new expansion, Destiny of Velious, is set to launch in early February, and that will add more content for the higher level gameplay (no level increase this time but an AA increase).
I'm very biased of course, but I think the game is well worth the time to get into.
Let us know if you have any other questions!