I'd highly recommend using Spy Sweeper (or the other anti spyware progs.) to make the localhost entries in the hosts file, for two reasons I can think of:

1.) inexperience/uncertanity doing it, as mentioned above.
2.) more importantly, when you update the definitions for any of these antispyware programs, additional URLs pointed to the localhost can be added to the hosts file. An example is when a URL changes, such as when "a.tribalfusion.com" changes to "b.tribalfusion.com". Some ad sites (esp. shopping assistance sites) are notorious for playing a game of leap-frog with this feature. Note that Tribalfusion.com is not one of these.