Wow, $10,000 is a lot to spend to not be a whale... But I'll spend on a character I like or just to get a farm done if I'm close. I typically won't spend more than 1 vault a month (Malak was my exception, he looked really cool to me) but I could totally see myself spending more if I didn't think the game would get a bit boring to me.
For me, there's no reason to log in every day if everything is maxed out already, that's usually the point in which I quit playing a game. And since I haven't found a game like this that is done as well or better, I limit the amount I spend to keep interest up.
For these reasons I wouldn't consider myself a whale, but someone who spends $10k even over the course of the 3 years the game has been around I would consider a whale. I guess that is subjective tho...
SN: I've only been spending on the game about 6-8 months now...