There is no best single all-in-one product but what johnb35 lists are excellente choices.
I have the paid version of Superantispyware (SAS) and I love how it can be configured. Plus they are constantly improving their product and updates are daily.
I also have the free version of Malwarebytes. No real time protection and the product has to be manually updated but with SAS, NOD32, and Online Armor I have had zero issues.