I would like to know the sites

For an extended listing and description of largely classical LPs with superior sound:
http://www.high-endaudio.com/index_ac.html - see "Supreme Recordings"

For an online resorce to reviews of various classical recordings (largely CD):

http://www.gramophone.co.uk - go to "Reviews"; you'll have to register, but otherwise access to an extensive database of reviews over the past 10 years or so is available.

http://www.classicaldigest.com - an extensive list

http://www.hifiplus.com - see "The Reviews" and work through the back issues from there.

Great response Rushton -- very useful. Thanks.