I'm a Christian who also practices Vipassana.
Let me qualify that. When I say I'm a Christian, I don't mean a Bible-Thumping Baptist. I'm an Un-Fudamentalist, Progressive, Postmodern Christian. I see a lot of value in other religions. I lean Unitarian/Universalist.
I get a lot out of Buddhist writings and philosophy. The Tibetan school of thought resounds with me far more than, say Zen. I studied it quite a bit over the past year. I tried several meditation techniques along the way and the stillness of Vipassana had a greater impact on me than any of the other methods. In fact, I meditate for 10-20 minutes before prayer. I feel like my prayer time is much clearer if I tame the monkey mind first. As a Progressive Christian, the Buddhist ideas of Compassion and how to interact with people who are suffering absolutely goes hand in hand with my beliefs. They build one another up. And the awareness I achieve during meditation, being able to hear my mind as separate than myself, and something I can change and whose patterns I can observe...I gives me experiential understanding of my soul as a separate entity from my mind...something I had struggled with before.
Living in a medium sized city in Texas, that's not something I make widely known. But I can honestly say Buddhism has helped my Christian faith.
As far as converting to Buddhism and having to rethink you're obligation as a Buddhist, I'm with JohnnyFlotsam. One thing that would be interesting to rethink is the meaning of some of the working tools from a Buddhist perspective. I think a Buddhist would find a much deeper meaning than, say a christian, in some of the working tools. If you're looking to rethink Masonry from a Buddhist perspective, I'd start there. I don't see the obligation as something that changes with a change in faith.