Depends on what sort of terrain you ride too (and how fast ya wanna go). I fitted a 48/36 compact up front some year ago and kept on spinning out in top gear on the flat. Changing to a 50/36 made all the difference.
Generally though with one tooth differential I guess you wont really notice unless in a race situation. Answer is to cycle more and worry about components less IMHO
WANTED: Kona Sex One rear brake canti hanger pivot thingy - GOT ONE!
I could be tempted by a 19" - 21" Dave Yates (mountain) frame.................and no I still don't do trail centreshttp://www.corrieyairack.org/index2.html