When Fairytale of New York was released in 1987 it was pretty much at the peak of my love of The Pogues. I remember being a little disdainful of the fact that they'd released a Christmas single, but I forgave them. When If I Should Fall from Grace With God its middle of side one position made it feel like a regular album track and I loved it all the more like that.
Things started to go bad with its 2005 re-release and the way that The Pogues have become another of those acts who only ever get given time around xmas (cf Jona Lewie, Greg Lake, Wizzard etc.) and suddenly it became a xmas standard. It has now charted five years in a row.
I saw Kirsty MacColl perform this with The Pogues a few times - it was sensational - now the songs ubiquity makes me uncomfortable using the word sensational anywhere near it. I switch off when I hear it.