The short answer is: Yes, pretty much.

Here is a website where you can print the list:
http://www.husvankempen.de/nunn/40_4_Ratinglist/40_4_mp/rangliste.html

CCRL Rating List

http://computerchess.org.uk/ccrl/4040/

CEGT

http://www.husvankempen.de/nunn/40_40%20Rating%20List/40_40%20All%20Versions/rangliste.html

SSDF

http://ssdf.bosjo.net/list.htm (hasn't been updated with Rybka 4 yet, but as you can see, Rybka 3 is at the top)

What about the features? Is your daddy a strong amateur, if so, how strong? Are you looking for a complete chess package, that is, GUI + engine? How about chess tutorials with it?
IMHO Chessmaster would be the best program for an amateur because of the features it offers, a strong engine with different levels and chess video tutorials to help an amateur to improve the game. Now, if you are a serious chess amateur with aspiration of becoming a very strong chess master, then Rybka would be one of the choices among other chess engines. Please note that there are free non commercial chess engines which are very close to Rybka chess strength, such as Stockfish 1.7.1. Therefore, you probably would do best to spend your money with a good chess tutorial program for your father and get the free non commercial chess engine.

I think the replies by now will have convicned you that Rybka is the strongest chess playing software in the world.  

Just a word of warning if you are about to buy Rybka for him.  If you buy it from the Rybka site in the UCI version he will not be able to run it without some extra software as the UCI version just does the chess "thinking" stuff without any user interface or for that matter opening book.

You can get freeware for the user interface but as it is a present I would suggest you buy a version that comes with a user interface (assuming it fits your budget).

The main options are Rybka+Aquarium from http://chessok.com/shop/index.php?main_page=index&cPath=7_1
and Rybka+Fritz style interface from http://www.chessbase.com/shop/productlist.asp?product=cp&subd=&user=&coin=

Note also that there are:
- normal single processor versions which will only ever run one processor core,
- and "Deep" versions that will run on single core PCs but will take advantage of multiple processors if you have a dual or quad core PC. 

Its just a cost difference and obviously the Deep versions play better if you have an appropriate PC.

Depending on your budget, the best thing might simply be to get the Chessbase version as it would give him online access to play against other chess players.  It is hard to believe but many still don't realize that they can get online and play other people of varying strength on the internet.  I guess you could also check out ICC or FICS of which the latter is free, but really the Playchess server IMHO is the most robust and prettiest interface which also works seemlessly with the CB version of the engine.  The Yahoo chess site is infested with computer cheaters so he will simply get frustrated there.  If he is into chess he will be able to not only play online but also watch chess matches by top GM's that are taking place all over the world.  You really don't need the very top of the line Deep Rybka 4 to analyze a human's moves and you can download for free on this website Rybka 2.3.2a, an engine that would probably crush Kasparov quite handily.  But if you must have the very latest then of course DR 4 is #1.  The only problem then is that you have to expect that free time of your dad is going to be cut dramatically .... but then come to think of it that might not be such a bad thing :)

what do you mean by 'chess program'? as someone said, do you have any idea how strong your dad is or what he would use the chess software for?

rybka 4 is the strongest chess -engine-, but if you dad is not serious about analyzing positions & games, it's very much a luxury & not a necessity. if he just wants to play it for kicks to say he got whupped by  the strongest chess program, that's fine (though junior is more likely to make his head spin while he goes down in flames). and keep there are probably at least a half dozen free engines that would demolish any human & most of them provide pretty good to top notch analysis as well. if he's more into training or playing with the idea of competitive games, there may be better options.

hello,

for a gift to your father, for a chess software, you can not consider only the chess engine ( like schredder, fritz, rybka, hiarcs, etc etc ) , but you need also to consider the GUI ( graphic interface) , like aquarium, chessbase, schredder...

every interface need some pratice, to master all the functions...

for the moment if your father has no chessprogram, you can choose GUI chessbase or aquarium on DVD very nice... schredder is only for download.

you can only consider chessmaster , the engine " the king"  is not the best , but only GMI can win against it ... and the gui chessmaster is very nice for the beginner's chessplayer.

cordialement

thierry

With the last settings recommended for blitz, I run a match between Rybka 3 and Rybka 4 on a powerfull 6 cores hardware.

after 261 games played, Rybka 4 is only 5 ELO stronger than Rybka 3 !

So for me the purchase is worthless !!!

regards

Right now Rybka is best chess entity in the universe. How do I know? Just check rating of engines and you will always see Rybka on the top.
Computer chess fans should always tell you this. It is strange that someone says Hiarcs is best - even Hiarcs fans should be a little critical to realise that their positions is not on the top.