BruteForce attacks are much better than dictionary attacks totally because of many reasons such as wordlist doesnt include all of words, it takes much more time to crack the password and so on.
However you can find good wordlists here:
http://www.skullsecurity.org/wiki/index.php/Passwords/But u perform dictionary or bruteforce attack use the ncrack tool first. Its a very fast pass cracker open terminal in backtrack and type this command:
Ncrack -v --user <username><target address>:<service port>
Example:
Ncrack -v --user admin 127.0.0.1:21
Goodluck and let me know if u have any problem.
CyberSpirit