I spent a lot. I didn't want to struggle too much in heroics and I had gobs of money from finishing storm peaks and icecrown at 80. If I had to guess, I'd say that I spent around 10k gold within 24 hours of hitting 80 on gear, and then probably another 20-25k since then

Edit: I also didn't want to run normal 80 instances at all - the gear drops are fairly horrible, the rep sucks compared to running heroics, and they don't give badges. I had extra money so I figured why not