Going directly to the sites instead of indirectly via Wikipdedia:

CEGT    http://www.husvankempen.de/nunn/

SSDF    http://ssdf.bosjo.net/list.htm

WBEC   http://wbec-ridderkerk.nl/

SWCR   was very difficult for me to find

http://en.wikipedia.org/wiki/Chess_engine_rating_lists#Ratings Click on the sources to attempt to get to the groups rating lists. In the first one I checked Deep Fritz 12 came 80th... I would ignore the link posted above mine as it seems amateurish, sorry Tanaha. edit: Actually the IPON one is in the wikipedia table. I hate when people flagrantly disregard the notability criteria for wikipedia, that is just one person doing it for his "privat enjoyment", and other times they insist on deleting very notable things that have been there for years.

Sylvester wrote on 01/24/12 at 17:02:53:

Interesting, I see they mention Fritz 11, but I already have Fritz 13, so how up-to-date is this list?

You can download free engines here:

http://www.chess.com/downloads/playing+programs+engines

I dare not stick my neck out here but point only to the obvious sales descriptions. Maybe some can launch a discussions based on them. I too would like to know the answer to your question. See:

http://www.chesscentral.com/Deep_Hiarcs_13_DVD_p/deep-hiarcs-13.htm

http://www.chesscentral.com/Deep_Junior_12_Chess_Playing_Software_Program_DVD_p/...

http://www.chesscentral.com/Deep_Shredder_12_Chess_Software_Program_p/deepshredd...

http://www.chesscentral.com/Deep_Rybka_4_p/deep-rybka-4.htm

http://www.chesscentral.com/chess_software_p/houdini-uci.htm

One thing I'm fairly certain about is that ChessCentral has the best shipping price options.

Hiarcs is promoted as the best analysis partner but it does not have the strongest rating. I would go for that explanation if this was a discussion about human players but is this the same for computers too? 

I hope those with considerable experience using the silicon brains will reply to this interesting question you've put forward.