How to avoid hard-coding Id values

So I have seen some tricks for avoiding hard-coding Id values in your Apex code, which I think is a good practice to follow, but they've always been sort of kludgey and inelegant. Today I saw one that I didn't realize you could use, and it deserves a place here:

    Id theId = [SELECT Id FROM <table> WHERE <criteria>].Id;

This is simple and elegant and exactly what I was looking for.