Is Bit Defender the best antivirus?

Dunno wether you can say whats the best as they all catch different trojans/virii better or worse than each other, really depends on how quick they are at getting updates out for new nastys!

or how good their heuristics are at pinpointing unknown or new trojans/virii ... Nod and Kaspersky do have good heuristics.. but so do the enterprise versions of McAfee ( but at a higher cost )

These days its not just AV that you need its a small collection of a few good AV and AntiSpyware apps to keep you clean.