I was just making a random comment. it's already been suggested that if you want to run a cassette in the back, then it's best for the chainring to be multispeed compatible too, not a single speed ring, which tend to be thicker in the teeth.

I think using the middle ring on a triple would be best for getting the full range. it would be best for chain flex in either the low or high end of the cassette. that flex will cause a little more wear on your chain, and take away a little more efficiency, but more importantly, it might affect your shifting. I don't know about others, but my shifting sucks when I'm in my 53/28, which is a combo that I try to never use.