As long as you are practicing "safe hex", that is watching what you download, keeping ads at bay where possible etc, I think you're good to go. I like to keep things simple, so I have very few security programs but have been careful to balance "easy" and "safe". If you're blocking plugins from automatically running and have a good ad blocker, that is half of the battle won right there. Also, remember that what may be "light" for me may not be for you. Computers are fickle little creatures, and you can sit two of them next to each other and have one piece of software run better on one than the other.