Sea of sorrows is the unofficial Oceania server, likely to be crowded and I'm not sure about general teammate latency. Maguum I think was pretty loaded, wasn't it Grave? Did you WvW at all? Zoobi is sure to pick a big server too.
See, I was thinking just wait until 3-5 days before head start and see what everything is looking like. I'll WvW, but it's not that important to me. If everyone else leans towards a high pop server that's ok, I can go lower pop and PvE with everyone still. Hopefully.