I have a VPS with 256MB of RAM that I'm setting up. I plan to eventually move the sites that I currently host on shared hosting accounts over to the VPS. The domains received an aggregate of 2,046,164 requests last month (according to traffic logs), though it can vary a bit up or down depending on the level of social media traffic that one of the sites gets.
Currently I've set things up as an Ubuntu LAMP configuration, which is using 137MB of the total RAM without any traffic coming in. I haven't really tried tweaking Apache2, as I'm unsure of what figures I should put in for maxclients and the related process settings.
I was told that Debian is a bit lighter-weight than Ubuntu, requiring significantly less RAM. Would it be a good idea to scrap my current install and go with Debian to save on RAM? How great are the savings?