jase:
VPS was something I considered going forward but I've pretty much ruled it out. It's a really risky proposition, you just don't know who else you'll be competing for resources for and if you're unlucky (in one of several ways) you can end up with a subpar experience.
SiteGround.com has a Cloud service which I've had REALLY good luck with.
It can automatically scale based on your load.
I've got two REALLY big clients (multi-million dollar E-commerce sites) on this service and I've not had a single minute of downtime.
Also, if the server you're on goes down, they automatically migrate to a new server for no downtime.