Thank you for the recommendation..
I ordered a PC680, today
Using google to search for any of the 3 or 4 battery names and part numbers mentioned in this thread will help you find the best deal today. Add the word "price" to your searches.
Prices vary and lead has gone way up since this thread started years ago.
My personal choice for the oilhead is the Odyssey PC680. And I buy them here:
http://sepbatteries.com/pc680-odyssey-battery?gclid=CInczJWW16wCFdIAQAodtmYK7A
$95 and free ground shipping in the USA.
Now you just have to wait for someone to find it cheaper.
I ordered a PC680, today