Generally the free options have smaller footprints on your PC. I'd rather go for free - why pay for something if there are perfectly good free alternatives?
The argument in favour of the paid-for suites is that they are just that: suites of applications that work together. But you can protect yourself against web nasties with the free software and a modicum of common sense: warez and cracks often house trojans/viruses etc, so don't go to those sites or download things from them. Some porn sites are also home to malware: be careful with them. Be careful who you give your credit card details to online and check your statements carefully. No software will stop you doing something stupid.