1. I am using linux (lol)
Just because Windows "hacks", viruses, worms, etc are reported in the new more, doesn't mean Linux is not vulnerable.
2. Anti-virus program would always slow down computer process
I notice no significant difference (actually, I should say I notice no difference at all in real world use) when my anti-virus is disabled.
3. Sometimes when you have to install something, the programs alwasy ask you to shut down the anti-virus software first, which again, slow down the computer process
Yeah, those couple mouse clicks are critical. It's far more important to save a few seconds than protect your data and not be a propagator of worms, trojons, etc.
If your computer or laptop are not critical, I suggest you not to install any anti-virus software.
I agree, this is terrible advice. And I almost say irresponsible. Not only do you risk losing your data (it's yours, I don't really care) but you run the risk of spreading virues etc to everyone else your PC comes in contact with. I am well aware this is less of an issue with Linux. But, as Linux grows in popularity, it's time will come. Don't use anti-virus software on your PC if you chose. Don't make the irresponsable recommendation to others... Use NAV, McAffee, or any of the freebies. Some AV protection is better than none.
\Dan