I've generated 5GB of rainbowtables with crack.pl and set to work. Visited md5decrypter.co.uk and downloaded their uncracked hashes(over 100K!) opened msfconsole loaded crack plugin and started to lookup the hashes. After 6 minutes, it looked up all the 100K hashes and cracked about 23% !!
One of the powers of the crack.pl framework is the ability to create rainbow tables from the wordlist, no other rainbow table cracker does this (correct me if i'm wrong) and the lookup of a hash is instant! almost no delay!
enjoy your holidays ;)