Localhost Doesn't Work In Listener.ora Or Tnsnames.ora

I want to be able to use "localhost" in my tnsnames.ora and listener.ora files but for some reason its not working.

just concentrating on the listener, when I have the following in my listener.ora the database doesnt register with the listener:

########################################
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))))
########################################

This is even after using the "alter system register" command. I'm checking whether my database is registering using "lsnrctl services".

With the following in listener.ora all is fine:

########################################
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.10.152)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))))
########################################

So why wont it work with localhost?! I'm running Oracle 11G on XP Pro.