Frequency of the Lord's Supper (Communion)

Yesterday, I commented on a blog post at the Lifeway Worship blog regarding the more frequent observance of the Lord's supper.  More and more evangelical churches seem to be practicing weekly communion.  I'm certainly not against this trend.  But it does make me wonder about the special nature of the ordinance.  Here at North Park we don't have a set schedule, but we try to observe the Lord's Supper at significant points on the church calendar - Good Friday, Christmas Eve etc.  It usually works out to about 4 times per year.  Some people would argue that observing "the Lord's Table" is too important, and that it should happen more often.  Others say that more frequent observation would over-ritualize and take away the special or "holy" feeling associated with it.  What do you think?  Should we do it more often, or is 4 times per year enough?