From my experience, it is better to spend a little more money and go for a Core 2 Duo and a good overclockable motherboard.
If you get an X2, you are pretty stuck when you will want to overclock in the future.
Say you get an X2 4200+ which is cheaper than the C2D E4300 and performs around the same. You are happy now.
But if u get C2D E4300 / E6300 now, you can OC to 2.4 / 2.8 Ghz in the future with some good cooling and the performance boost you get would be beneficial with heavy apps / games which could choke / stutter on an X2 which might not reach clocks above 2.9 Ghz even with good cooling.
Just my 2 cents.
If you get an X2, you are pretty stuck when you will want to overclock in the future.
Say you get an X2 4200+ which is cheaper than the C2D E4300 and performs around the same. You are happy now.
But if u get C2D E4300 / E6300 now, you can OC to 2.4 / 2.8 Ghz in the future with some good cooling and the performance boost you get would be beneficial with heavy apps / games which could choke / stutter on an X2 which might not reach clocks above 2.9 Ghz even with good cooling.
Just my 2 cents.