I have been working with a pattern called "composite specification" that uses lambda expressions in this way. We are looking at combining it's use with NHibernate, which can turn the composed lambdas into SQL. Seems like a pretty powerful, flexible approach to me.

When it's time for some heads-down coding, I like to be able to turn the lights off. I can't stand short- or no-wall cubes because when I see movement in my peripheral, I look up involuntarily.