For some people, the social aspect of the game keeps them going. This is how casual players who don't have a chance in hell of being useful in raids enjoy the game. They can come on and kabitz and, if they decide they want to do a little raiding, a strong group can carry them. I know a lot of folks who enjoy this style of play past level max.
Others like helping newbies in a guild do quests or achieve goals.
There are folks who enjoy crafting or gathering and the prospect of these things keeps them interested.
For me, I only wanted better gear and more trophies. That might sound sad and pathetic to some folks. Nevertheless, to be perfectly candid, that's what I wanted. I enjoyed doing end game game raids, progressing through end bosses, and getting better gear. I think Humanoid somewhere up above made the same observation I'm going to make now. ...Or, more appropriately, I'm going to agree with him wholeheartedly. I hate dealing with end game because after you've made your kick-ass healer and have her decked out with stuff and You've finally made something of her, the xpac comes out and you're stuck moving ahead. That could be good, right? Not really. You end up grinding grinding GRINDING for rep, doing the same sorts of daily quests, jumping through the same hoops, trying to keep a group of often volatile, egocentric, and vain team-mates together, and then filling in the spots when folks drop out for various reasons. For my part, I have never fought with folks about gear, but I've seen more people leave successful groups because they deserved first dibs than any other single reason. At the end of all that, I just coulnd't stomach the thought of playing a new MMORPG.
Hurlie had good advice, sure. Play for the other things and don't get stuck on gear and prestige. Sadly, that's not what I want. I have never seen an MMORPG that was as good at the other RPG aspects as a good single or lan based RPG. Once I got sufficiently jaded, it was all over for a while. It's been several months since I've played one and, frankly, I'm glad raiding isn't sucking up every bit of free time I have any longer. That goes double for the little lady.
On a different topic, I started out fairly positive about ToR, but as time went by and folks kept spitting vitriol at WoW and acting ilke, based on the Star Wars license, ToR would clean house, I found myself quietly rooting against it. I loved Star Wars when I first saw it in theaters in... 1977? I still have nostalgic feelings about the franchise but, for all of its considerable influence in pioneering successful Sci-Fi cinema, I don't think I'd hold it in the same esteem if it came out now. I love the fact that Star Wars made Sci-Fi truly cool, but that's no reason to buy a game based solely on the license.