Which security mode is the best for wireless router: WEP, WPA, WPA-2, RADIUS

We're talking about home wireless router security for your regular wi-fi connections. The Linksys routers provide following security modes: WEP, WPA-Personal, WPA2-Personal, WPA-Enterprise, WPA2-Enterprise, or RADIUS and I see that there are mixed opinions on which is the best mode among these. From what I read online, WPA types have been known to have performance issues (lesser speeds and frequent disconnections).

I'd want the discussion to be about -

1. Which mode is easier to crack via wireless network password cracking tools like backtrack?

2. Which security mode offers better performance?

3. Which security mode is better 'overall' - difficulty in breaking, no degradation in performance etc.

Would love to have technical insights on each of the recommended mode.