To each their own. It always fascinates me to hear about Java/.NET environments that massive. Do you only work on 1 project for months at a time? Do you not ever need to reboot into another OS? Is your laptop power efficient? Do you have a separate machine just for Gaming?
I mostly program in languages like Ruby & Perl using Vim. Even with my decked out version that has 35 plugins, and some other bells and whistles, I'm on average using 20 MB of RAM. Open/Close is near instantaneous.