As I mentioned above, Domain Pop is probably one of the best overall because it displays by website so, unlike most, you don't have look at pages and pages of backlinks from one forum sig link. This is really nice if you have sitewide backlinks, forum sig links, or blog links on main page. It saves you A LOT of time checking backlinks using Domain Pop. http://www.smartpagerank.com/ is real nice because it also shows backlinks, with PR and if it is nofollow.
yahoo is good to check all the backlinks the other backlink checker tools do not show the whole list and sometime result varies from one tool to another tool.
I do use Backlink watch but its got this annoying thing where it saves it till a date. It has saved my report till "Saved till September 8, 2007". How do I get rid of it? As it won't re-count my backlinks until that date (I think).
may I ask a stupid question? I am wondering, how come that Google PR is based on the number of backlinks and Google does not show accurate results of those backlinks at the same time?