If you're not planning on scaling up and down on a regular basis I would recommend a VPS. Jed Smith mentioned two options for that and another choice for a VPS is http://prgmr.com/xen/ which I've used and am happy with. They don't offer as many options as Slicehost or Linode, but they offer more RAM per dollar than most other providers I've seen. They also don't offer any wizards or ajax console access or other high level features. However, if you're ok with setting everything up via a command line console they are an option you should consider.
