I have been trying to answer this question but I haven't found an specific answer to my situation. As I want to pay for what I need, I thought I could get a good answer here.

I have custom made forum (rather than a built-in forum like the ones you can find as plugins, e.g. WP-Forum or phpBB type of software) in Django. I don't want to use Apache and modwsgi because it's usually very memory-hungry and I can't afford a big server. I prefer a combination of nginx and gunicorn which I think is very efficient (maybe you can also tell me what you think about that).

I'm expecting to receive 10,000 to 20,000 visits each month with 15,000 to 30,000 page impressions. I have reviewed some cloud services like Amazon EC2 or Rackspace and other more traditional services (Linodo). This site won't use videos or big images and I certainly don't need a huge amount of bandwidth (200GB would be definitely too much). I need shell access so shared hosting is out of the question.

What do I need to run a website like that without problems? What about RAM? 256MB would be enough (that's the amount of RAM offered by small instances in Amazon and Rackspace)? Do you know of any alternative to those I mentioned?

If you need more information to provide a useful answer, please don't hesitate to ask.

Thanks a lot.