Re: differences between mysql.exe file in c:/mysql/bin
From the MySQL documentation:
mysqld Compiled with full debugging and automatic memory allocation checking, symbolic links, and InnoDB and BDB tables.
mysqld-opt Optimized binary. From version 4.0 on, InnoDB is enabled. Before 4.0, this server includes no transactional table support.
mysqld-nt Optimized binary for NT/2000/XP with support for named pipes.
mysqld-max Optimized binary with support for symbolic links, and InnoDB and BDB tables.
mysqld-max-nt Like mysqld-max, but compiled with support for named pipes.
A more detailed description: http://www.mysql.com/doc/en/Windows_select_server.html