For me it is east commons. It was the first zone I went into when I left Freeport at 5th level. I zoned in, and all the noise, all the mobs. The tunnel was used as the place to go and sell things. So /auction was always going with all the things. I would hunt the orcs on one side, and the undead on the other. Die alot. But always the EC tunnel /auctions. It was like a mystical, magical ride. I found a guide on how monks could FD flop and farm the named goblins in Solusek's Eye. So I went in, died alot, but figured out what the guide was talking about. I'd take 5 or 8 drops out at a time, run to the EC tunnel and find a spot along the wall and start auctioning off my newly looted items for 200-400pp each. I was so surprised that they sold. Ever since then, I get nostalgic when I'm running through east commons, remembering the time I sold an item and got 10k plat. And then the slow, very slow walk (encumbrance) to freeport, and then the bank so I could deposit it.