The foiled plot to blow up ten planes is the big item in the news right now. Thank God that a big tragedy was averted and lives saved. When things like this happen, I always wonder if it was in answer to someone's prayer that God would prevent it.
In her autobiography, St. Therese had a reflection about things like this. It's been a while since I've read it, but it was about how we should be even more grateful to God to realize what evils he prevented us from reaching us.