I think I once had about 25k back when I was a regular user before 2008, and I was ecstatic. Right now I'm in my "upper range" by having 15k. My account usually stays in the 0-5k range, because I love the cheap crap in the stores.
But I rarely visit. I'm surprised at how fast gold builds up here now. I've earned 2k, and I've only been posting in the forums for an hour!
Like many people have said, gold is so much easier to come by what with BG, HOC, and zOMG and especially if you spend irl cash. Rich is subjective but my personal view of Gaia wealth going by account worth is: 0 < impoverished < 100k < poor < 1m < low-middle < 10m < middle < 50m < well-off < 150m < rich < 999m < If you have b-b-billions that's filthy stinking rich.
It's hard to say what is normal these days. I used to figure if you could afford to buy MCs every month, you were doing pretty good. But, that was in a time when MCs were the only big-ticket items.
When the cash shop opened, I felt I was doing well if I could have one or two of the latest EIs. But, there's so much other stuff now. Maybe today I would base things on how many RIGs I could buy per month, but I never play RIGs, so I don't know.
All-in-all, it doesn't really matter how much you have in comparison with everyone else. What matters (as far as virtual finances go) is whether you can afford whatever it is that pleases you. That could be anything. It's not necessarily the most expensive items.
I have a little over 1k. I never have a lot of gold. I don't have the time to make it, being that I am a parent of a small child. My resources, like time and money, go to him first. I have spare money for maybe $10 in GC every other month.
I wish I could just afford the things I want, but I don't bother getting butt frustrated over it. It has made me less ambitious about getting things I want, so I donate to other people more often.