If you've been married for less than 2 years, and your I-140 is approved and your priority date is current, your employment-based GC will probably approved within a few months, and it might be better to wait till the end of the summer and see what happens with the employment-based GC.
The employment-based GC will be a 10-year green card if approved, whereas the marriage-based one will be a 2-year conditional card if you've been married less than 2 years, and you'll have another round of paperwork and possibly another interview 2 years later to convert to the 10-year card.
But if you're going ahead with the marriage-based one anyway, you don't have to cancel the existing employment-based process. You can have both going at the same time. Near the end of the process they may ask you to withdraw one or the other, but there's no need to do that unless they ask.
Last edited by Jackolantern; 6th July 2012 at 01:00 AM.
PD: Jan 2003 (EB3 rest of world)
I-485 Approved: July 2007
I am a layman, not a lawyer. What I write here is not official or professional legal advice. In addition, my answers on this forum are specific to the scenarios discussed in each thread and should not be generalized to other situations.