I'm feeling pretty good because I've hooked up a laptop to my Yamaha
Clavinova electronic piano and it's working beautifully.  However,
even as a novice, I can tell that the quality of the MIDI files varies
widely.  So here's my question(s):  Where can I go for high quality
MIDI downloads?  I'm interested in all sorts of music, so maybe
there's more than one answer.  A music site which provided ratings of
MIDI sites would be excellent.  Thanks!

kj...

I empathize with your excitement. I have my Kurzweil K2500
hooked up to my PC's midi out, and quite enjoy hearing good
midi files play through it. And, as you've found, there are
vast differences in the quality of those available.

In the past few years, you can imagine that the trend toward
turning a profit on the internet has resulted in the sites
which offered the best midi files beginning to charge for
their obviously superior downloads.

Still, you can obtain a reasonable degree of quality for free.

As for a site which reviews midi sites, the best choice
would certainly be the site which is listed #1 in a Google
search for both "best midi files" and "best midi sites",
which is the midi page on StartingPage.com:
http://www.startingpage.com/html/midi_file_music.html

As you may know, Google ranks a site higher if it is a
consistently popular page on the topic of the search.
Additionally, I found that it contains many of the 
higher-quality links I have personally bookmarked over
the past few years. This indicates not only their 
agreement that these sites are useful, but also that
these sites have not 'gone away', as many bookmarks
are likely to do.

The first is a link to 'Standard Midi Files on the Web'.
The link is obfuscated and the final result is merely
a duplicate of one of my bookmarks. Use this instead:
http://www.manythings.org/midi/

The second link is also obfuscated with referral language,
but the ultimate destination is for a midi search site:
http://www.musicrobot.com/

The third link is also obfuscated with referral language,
but resolves to Harmony Central's list of (unrated) links:
http://www.harmony-central.com/MIDI/files.html


About.com has an article regarding some of the legal issues
which have resulted in the shutdown of some of the best
free midi file sites, entitled 'Massive MIDI Sites -
Large archives almost gone':
http://mp3.about.com/library/weekly/aa040102.htm

About.com offers the following resources on links from this
page:
http://mp3.about.com/cs/midifilesmore/

The Midi Composer's Exchange:
http://mp3.about.com/blexchange1.htm

Melody Lane:
http://www.melodylane.net/

Don Ferguson's Tin Pan Alley:
http://www.geocities.com/dferg5493/songfiles.htm

And About.com's page linking to different styles:
http://mp3.about.com/od/midifilesvaried/

MP3-MIDI.com also provides useful links to About.com's
collections by style:
http://mp3-midi.com/


Another site which offers links with a moderate degree
of review is TigerBill's site:
http://www.tigerbill.com/subjects/dmidi.htm


Another good resource is The Midi Farm:
http://files.midifarm.com/files/


WebRings are another good resource on any topic.
Here is the midi webring page:
http://l.webring.com/hub?ring=midi


And finally, PRS.net has changed to ClassicalArchives.com
and offers some of the best classical midi files around:
http://www.classicalarchives.com/midi/


Please do not rate this answer until you are satisfied that  
the answer cannot be improved upon by way of a dialog  
established through the "Request for Clarification" process. 

sublime1-ga


Searches done, via Google:

"best midi sites"
://www.google.com/search?q=%22best+midi+sites%22

"best midi files"
://www.google.com/search?q=%22best+midi+files%22

This is just what I needed.  I'll play with the links you've provided.  Thanks!