I came across this website today:
www.visualdeepsky.org/search.html
Really good website. Simply select the catalog (eg. Messier) and enter a number (eg. 42) and an instrument size (say 4" scope). Now you will get reports posted by users who have written an acount of their visual experience with this object. Provides a very good idea as to what one can expect to see with a telescope. Well worth checking out!
  