I have no real experience in this matter, but based on what I have read around the internet and wikipedia (the only sources of truth), Rybka is the strongest engine, therefore I think Deep Rybka (multi-processor) is technically the most superior engine for analysis of moves.
The other thing about Rybka, which maybe more knowledgeable members can better explain, is that apparently it is not programmed primarily as a brute-force calculation machine like many other engines, and so its move selection factors strategic/positional concepts better than the other engines (without sacrificing tactical accuracy), hence it always wins the computer tounaments.
Hello
Im trying to make a habit out of analyzing my games but the only software I have at the moment is an old copy Fritz 8. Between Rybka or newer versions of Fritz etc... What is considered to be the best or most thorough when it comes to analyzing your own games? Thank you in advance for for any advice.