CoD series, BF3 and similar. But i don't care about very high details. And monitor resolution is only 1280x1024
Hmm..then an AMD Llano system is ideal for you! A8 for CPU with 6550D IGP along with 4GB high speed RAM (atleast 1866 MHz to drain the whole power from IGP.) Try it without discrete GPU, and if you 're fine with it OK. If not add another 6670 for hybrid crossfire and you will be good!