On Emacs ... you still have to pay attention to the loaded extensions, and if you've got dozens of them (especially the Jdee extension, with all the dependencies) it can be as bloated as a full IDE (and it shows in startup times).
I've ran VS 2008 on my almost-six-year-old laptop (P-M Banias 1.4 GHz, 1 GB DDR 333, 80 GB 5400 rpm) and I would not hesitate to call the experience "comfortable". What are the specs on your netbook -- is it really that much worse?
On Emacs ... you still have to pay attention to the loaded extensions, and if you've got dozens of them (especially the Jdee extension, with all the dependencies) it can be as bloated as a full IDE (and it shows in startup times).