If I’m not mistaken the recommended size for swap is always the RAM size. But hey, Google is my friend and I found this:
http://wiki.linuxquestions.org/wiki/Partitioning_guidelines
From the Swap space paragraph:
Almost every Linux system will need swap space. The classic piece of advice is “swap should be double the amount of RAM you have”, though this is not a rigid guideline. Another guideline is to have at least 1x your RAM size, but this also isn’t a fixed, absolute requirement (this used to be necessary for linux, but not anymore for recent versions). It depends mainly on what applications you want to run. Applications like video/movie editing, 3d rendering, large image editing, database servers and web application servers can use a lot of memory and if you don’t have that as RAM, it will need a large swap space.