Well what is the best is a matter of opinion. Best thing to do is research what you are thinking about geting, and then make an informed decision from there on what you think may be best.
You can start with this link.
http://www.gnutellaforums.com/showth...hlight=adaware
You can also search(upper right between f.a.q. and home) for various things you may have questions on. That is how I just found that link.
Best of luck