Please help me by letting me know which OS X installation is best for the following configuration

Computer specs:
Manufacturer: Acer
Model Name: Aspire 5738zg
Processor: Intel Pentium T4500 @2.3 GHz, 800 MHz FSB
Graphics Card: ATI Mobility Radeon HD 5470 - 512MB up to 2301MB HyperMemory
Memory: 4GB DDR3

Thanks in advance!