Today I had a realization; the only thing left in the game is going to be doing the same thing over and over to grind for better gear to run the same thing over and over to grind for better gear so I can do...

That doesn't seem like a lot of fun, to be honest. I'd never played a WoW-style MMO before this one, and now I realize why. The story of the game, the VO and all the rest really helped while doing my class quests and I really did enjoy the game. But now that I'm at level 50, I realized that my thought of going back and doing the other class quests wasn't any fun either because the vast majority of the content is repeated; class quests are only a portion of it and the story just isn't enough.
So, I'm cancelling my sub. It renewed a few days ago, so I'll be around for another month or so, but when I had the epiphany a little while ago that there wasn't any more fun to be had at level 50, and that all I really had to look forward to was repeating the same area over and over ad nauseam just to get the right loot drop... not so much.
The fact that my personal life has gone to about six shades of hell lately probably doesn't help much either. I'll still be around on the forums, of course.