Have you thought about postgres replication ala slony? I'm in SB and I am well versed with slony replication so I could offer my $.02. I just learned about rightscale and ec2 today, pretty darn cool. I am going to try out ec2 and possibly rightscale as I learn more. I'm used to having remote servers I access via IPMI, but EC2 seems to put that to shame. One website I do does 20 TB/month and I have a ~$40/gbit pricing structure so EC2 doesn't make sense, but for the other websites it is probably a good idea. One issue is security, I wouldn't want amazon snooping in on my data, esp. since I am a competitor of sorts. So I would probably encrypt everything with truecrypt or dm-crypt. Definitely interesting territory here.