Avira AntiVir - with the guard and scan heuristics cranked up to 'high'. I used to depend on AVG, but it's nowhere near as good as it used to be on the detection front - which nearly resulted in the death of my desktop recently, due to a couple of quite nasty viruses sneaking through.
With my AntiVir settings, false positives are quite common. If anything is flagged with heuristics, I tend to get the file checked by uploading it to one of those multi-virus-scanner sites. They email you back with the result, after scanning it with the top brass of available virus scanners.
:R: