Frankly, none of them will tend to catch much. Most malware these days is a direct result of you clicking on something you shouldn't have. I've seen plenty of cases of Symantec Corporate and MS solutions grabbing the symptoms of malware, but not cleaning the source, which usually means firing up things like Combofix and Malwarebytes.
Defragging is still relevant, but not strictly necessary. You can schedule Windows to do it when you won't be using your computer, provided it's on and booted into Windows. I honestly can't remember the last time I've defragged my PC...I do remember using Norton Utilities to do it in NT 4 and having it bork my Office 97 install every time.
