The only time I've had an issue with 2GB is when I open a virtual machine. 2GB has handled everything else I've thrown at it over the last couple of years, and as a software developer I can tell you that Eclipse is not a lightweight bit of software.
I guess a lot of people just want to make sure they don't run out. I have thought of adding a bit more but never seem to get around to it. In reality, 2G seems to be fine for me--and I usually have a lot of stuff running--like right now with a bit over half being active.