I have two IDs I have used for a while. Really, they should be considered consecutive as I stopped using one and started using the next, but I go back and make sure the old one is active still now and again. It's the lower one. Been on ebay since 4/98:
#1 has 5656 unique as of right now (11,739 total...I do a lot of repeat business and multiple item buying)
#2 has 1629 unique, 3280 total.
There were a few other IDs I used as well that I quit using with maybe a few hundred more FB.