Since setting up my development environments on Mac OS X Lion (brand new macbook air purchased in January 2012), I have noticed that resolving to a virtual host is very slow
Make sure to put the IP v6 entries not in the line with localhost
::1 localhost
the IP v6 entries go in a separate line
fe80::1%lo0 here and_here
It is sometimes really fast now, but there are rare exceptions where the old lags come back. They might however be based on other reasons.