There is nothing wrong with still using OS X 10.6 Snow Leopard.
Many, myself included, still are using this version of OS X.
Just make sure have updated Snow Leopard to 10.6.8 as Kappy suggested and use his supplied link.
Snow Leopard's Safari web browser version is out of date and currently a vulnerability in the OS.
So, switching to the Firefox web browser is the best thing you could do to protect OS 10.6 Snow Leopard and your data from any malicious threats from the web.
While it it is not the latest and greatest OS X version and Apple has stopped supporting security updates for it, Snow Leopard is still a usable OS X and Apple still sells this on disc, currently,
OS X Snow Leopard still functions well for me and I still need it to run, older, legacy software I can no longer afford to update/upgrade.
You have options if you wish to upgrade your OS X version in the future. The free Yosemite or you can pay for a code a download and install either 10.7 Lion or 10.8 Mountain Lion depending if your machine has the minimum hardware requirements for either 10.8 or 10.10.