Everyone knows firefox has a notorious memory leak issue, and it drove me crazy as a web developer. Yes, I know Chrome exists, but it doesn't have vimperator plugin!
So, Mozilla has released firefox version 7. This particular release claims it drastically improved memory handling for certain use cases. Good news, and I went for a trial.
After using the new version for the whole morning, with currently 6 tab open, memory usage is 254MB.
Yes, it is fixed, at least seems it is so far.