The rumor is May 8 or 9, but I've seen many a rumored data come and go in the past several months. Since the release will come some time after the announcement (I think it'll be announced at WES later this month), you will have to make a decision on your Droid before then.

Keep in mind too that you can upgrade next March if yours is the primary line. That way, you can enjoy your Droid for a while and learn what the new device's bugs are before committing.