I don't know wich is the best ,,can anyone give me a opinion ?
I look for an AV that can scan emails as they arrive and webpage link scanning when clicked - - this is a proactive approach and much better than scanning files repetitively. I also ignore any suite that includes a firewall or ad-blocker. (Windows FW is great and you have to disable the AV version, and you can find all kinds of ad-blockers and may wish to swap for another anyway).
I've been using Avast! Free for years now and love it.
I think a decent ad-blocker and some common sense is good enough for 99.9% of us. Block ads, and if something doesn't 'seem' right, then don't open or install it. Both Windows and OS X now have pretty damn good inherent protection, you almost have to completely allow something in to get 'infected'.
Basically, don't believe internet ads, and don't install anything you didn't specifically ask for. If something asks you to install it it is likely no good.
I also like Trend Micro...
but it is not free... at least mine was not.
On some of my machines I run MSE.