Starting on a new server?

A reader wrote me about the interesting problem of what would be the best choice of server to start a new career in World of Warcraft on. Would you rather start on a brand new server, or on an old one that is around for 2 years?

Good question, but I didn't have a good answer to that. I know that whenever a new server opens up, there is a rush of people starting new characters there. But that has certain disadvantages: Right now most of the new characters are blood elves or draenei. And more importantly, a large percentage of the players that start on a new server don't stay there. Once the shine of the new has worn off, they either go back to their old server, or they start on the next new one. On the positive side a new server gives you the opportunity to start with a fresh economy, and with lots of other low-level people to group with.

An old server is more stable population-wise. And apparently Blizzard has managed the hardware upgrades and server migrations so well that few old servers have problems with overcrowding. On the old server I'm playing the Burning Crusade hasn't caused any queues. The advantage of an old server is that there is lots of money in the economy, so you can make money easily by for example selling copper. The disadvantage is that generally there are few other low-level characters around, although of course right now that isn't so bad, due to some people having started new characters of the new races. And once you reached a higher level, I don't know how easy it is to get into a good guild on an old server, and really be accepted.

So, what would you advise? What other advantages or disadvantages do you see between starting on a new server versus starting on an old one?