I personaly used the trial version of spysweeper once and i don't think it do any good. there is goining to be something there every time you scan your computer. they will just keep coming back. and samething can be said with the other two programs.
If I were you i will just get the real version of spysweeper and Giant Antispyware. these two have the highest rating by PCmagazine. I use them and i think they are very good.
I also use Nortion internet security 2004 Pro. but let me say this Norton can solve as much problems in your computer as it can cause. none the less it is better to know that there is not as much junk in the computer.