Need advice on purchasing/building a new PC

First of all, I don't need the high end gaming PC. I'm really looking for something at a decent price that will last me a few years. For example, this is what I have had for 4+ years and it has gotten me by pretty well:

Lenovo IdeaCentre K220
Quick SpecificationsSee all specs
ProcessorIntel Pentium E5200 / 2.5 GHz
Memory4.0 GB / 4.0 GB (max)
Hard Drive640.0 GB - 7200.0 rpm
Operating SystemMicrosoft Windows VistaMicrosoft Windows Vista Home Premium 64-bit Edition
Optical DriveDVD-Writer - Serial ATA
Graphics ProcessorNVIDIA GeForce 9300 GE TurboCache
Graphics ControllerPCI Express x16 - Plug-in card


I mainly surf the internet with my computer but would like to be able to play games on it from time to time without having to worry about it not handling them. I bought this one refurbed and have no problem doing it again since I can more than likely fix any problems.