Suggestion for a good chess engine on Linux I'm using GNUChess with the Knights client (Knights doesn't seem to be THAT mature; crashes are common). Is there any equivalent of Chessmaster on Linux? What about good clients to play on servers like FICS.

I currently use Jin to play on FICS. But I think Jin doesn't expose all the functionalities of the server, e.g. chat isn't there in Jin.
Engines:


Toga II (Package).
Glaurung (Package).
Fruit (Package).


All three are installable via Ubuntu Software Center and all three are UCI compliant (ie. so runs in Chessbase Fritz, Chess for Android, and/or Arena GUI). Arena is used with FICS so you should be able to use all 3.

Except for Glaurung I used both on occasion and was very satisfied with them.  

Installation:

sudo apt-get install toga2 glaurung fruit