Well, md5 is secure enough.
Md5 is a one-way hash algorithm, wich means md5 "encrypted" data cannot be decryptet, whatsoever. It's definitly secure enough.
What you need to worry about is the code surrounding md5, passwords required to access the database, and of course the account-passwords (i.e. login e and password e will take very short time to brute-force).
