HELP!

I'm having a weird day. Including maybe yelling at some people during a meeting.

So I thought "How nice would it be to go home and watch some Alias?" But I don't have any on DVD.

Question: If I were to buy some Alias on DVD, what season(s) should I buy?

BTW - I've recently watched the entire first 4 seasons in syndication and I watched the fifth season when it first aired, so I think I've already seen every episode.