I was raised reform, and I suspect there may be a few people who don't consider me Jewish. To me, Judaism is Tikkun Olam. The most important mitzvot are those that rescue and encourage life. I don't belong to a synagogue - but I rescue stray kids and bing them home to live with me.
What I find interesting in modern Judaism is (to put it a bit dramatically) that just like in the first Temple era there are various Jewish movements, Rabbinic Judaism is not the last word, and we can encourage growth by pluralism within. the hot debates inside Israel between the secular public and the Chief Rabbinate is a testament that Jewish culture is much more vibrant than a monolithic interpretation of old Halakha.