Trend Micro anti-virus
I was really less then impressed when I bought Norton A/V some years ago to find that it was one serious resource hog. My computer literally slowed to a crawl when it ran an a/v scan of my hard drive. Not impressive. Trend Micro though I noticed on a friends computer was quite fast and had a far smaller hit resource wise. Its a shame that most people only go with the big brand names in the a/v market. Trend Micro is actually quite nice. You'd think the larger companies would make a serious effort at making a better product.