Someone once asked me why, in the Liturgy of the Hours, we only use the Psalms (and canticles) from the Bible, and not other texts. Occasionally you also hear people comment that "other" books ought to be used for the Liturgy of the Word at Mass; we've heard those same biblical readings so many times, we need something different.
This evening at Vespers, Psalm 46 spoke so clearly to the situation in Haiti, it would have been impossible not to pray it in the name of those suffering people: God is for us a refuge and strength, a helper close at hand in time of distress. So we shall not fear, though the earth should rock...
I remember during the worst of the genocide in Rwanda and Burundi that it was Psalm 79 that fit the situation to a "T": They have poured out blood like water...; no one is left to bury the dead.
Yes, we do pray the same Psalms over and over in the Liturgy; hear the same Scriptures year after year at Mass. But every time we do, we are hearing them from a world that is different, so that those "same old" readings are addressing new situations, and the Psalms are giving us words for prayers that, until now, had never really entered our hearts.