Originally posted by Life
I've have been using the domain in commerce since the inception.
This is your strongest claim for the domain. If you've been using it for commerce, then you have certain common-law rights to the TM.
However, there's a big difference between the way ICANN's arbitration providers treat these cases and the way civil courts approach them.
If you get notified of a UDRP challenge, make sure you provide as much documentation as possible regarding your commercial use of this domain: emails, dated screenshots, financial transaction info, etc.
Also, I recommend you do not approach the TM holder.
However, if they approach you with an offer, take it under consideration if it's in an accepatable range, and negotiate from there. But do not, in any way, indicate it's "for sale" prior to an offer being made to you.
Unless there are other circumstances affecting this situation which haven't been stated in this thread, I'd say you have a pretty good chance of withstanding any challenges to your registration of this domain.
Miles