That book by Sider is AMAZING. It is really challenging and I think it is a must-read for the Church and Believers.
A tip on tithing -- set aside that part of your budget first and then conform your other spending to what is left, rather than the usual practice of tithing out of what he have left over. Actually, don't get my started on this, because there is so much encouragement in Scripture to give, and yet Believers often look just like the world in terms of how we tight we hold onto our "stuff". I struggle with wanting lots of stuff, too -- it's hard in America, but we have to swim against the cultural stream.

I've heard of the Sider book, but haven't read it. I have another recommendation: Craig L. Blomberg's "Neither Riches Nor Poverty." It's a survey of Biblical Theology (Genesis to Revelation) on the topic of money, etc. It's well balanced (Sider has the reputation of being over-the-top ... though I've not read him) in my estimation.

Hey Miles, what church do you go to ... I saw you help with the youth group, but I didn't see the church name.

The book is actually "Neither Poverty Nor Riches"; also, Sider's "Rich Christians in an Age of Hunger." For a different perspective, check out a book called "The Good of Affluence" -- I was all set to reject every page of it, but the author did a good job with his work up until the part I read. I had it stolen (with all my luggage) in San Francisco.