Surprisingly, MSE is quite minimalistic. It doesn't have an overbearing interface and it doesn't toss security pop-ups at me. It sits silently in the background.
I used BitDefender a while back, I liked it because it was minimalistic but it's latest interation is more intrusive. It seems everyone is trying to imitate Symantec's Norton Antivirus by having an over-the-top interface and commandeering your OS. Kaspersky is alright and more managable than Norton or McAfee, Panda is pretty good too.
A while back I also checked out
ClamWin (opensource antivirus), it has a decent detection system but it lacks an active resident shield, so you have to manually scan stuff for it to be effective at all. Basically it's great for the already cautious user, not the best solution for the average user.
Yeah, where is Scott?