I have been using this BBS board for a while and I got lot of information from people here. I would like to share my experience with whoever is interested.
I140 (NIW) filed, 12/2003 (I was still a graduate student then, biomed research)
USCIS RFE, 12/2004 (they asked for further evidence that addresses my work will fit in National Interests and will immediately benefit the US)
Response to RFE, 01/2005 (got a couple of more ref letters, wrote a detailed Research Plan)
I140 approved, 01/2005 (9 days after response to RFE)
Like many people here, I have come through a long way to get this point. What I believe is the most important for getting your I140 approved: the reference letters and your self-description of your job. Publications counts, but are not very important (just my opinion). I had only 2 publications and total 12 citations.
Hope this would help and encourage many...