Numerical precision - Update
I just got a post from a few people including Christer Ericcson on the importance of scaling your epsilon value. Although my post is right to some extent (it is a good start, and definately superior to doing absolutely nothing), unfortunately it is also inadequate. In addition to a fixed tolerance, one should also consider scaling the epsilon value so you have a relative tolerance level. For more information see his response on my last blog entry about Numerical Precision.