Options Multiple Site Deployment On One Box

I was wondering if there was a strategy to consider when running
deploying multiple low traffic app’s on the same box. i have 2 or 3 i’d
like to deploy on a virtual box (slicehost probably). In the past I’ve
deployed nginx & mongrel cluster, but i’d like to be able to run 3 apps
on one 256/512 box, and only when i get some traffic up actually
dedicate out some more resources to an app.

Is there a advantage to using passenger here, or nginx etc…

any advise would be gr8.