keep Lighttpd + FCGI ?

I'm considering moving from my Lighttpd + FCGI setup to some server (Apache, Nginx, or Lighttpd) balancing a Mongrel cluster. As you know, everyone has different opinions about which setup is best.

I have 512 MB VPS, currently running the LxAdmin control panel.

I have two questions:

1) Can anyone with similar setup recommend a good Mongrel cluster- based setup for a VPS of this size?

2) One way I'm looking to free up resources is by not using a control panel, say if I move to Nginx. I'm certainly not a seasoned admin, but I can manage via the command line. How necessary is a control panel, in your experience, given that I want to manage a single Rails app that on my VPS? What features are most necessary? (I think i would need to manage DNS and database backups at least, right?)

Thanks so much for your insight.

Oops, posted twice. Please disregard this one.