In that case I would suggest going for an
i5 750 CPU and P55 motherboard.
This motherboard is a good price and overclocks well. If you are able to spend £15 more,
this is well worth it. Also, if you haven't already got one - get a CPU cooler. With a decent one like
this you can expect to get a nice 1GHz overclock with the i5 chip.
Using the same RAM that you picked, its good stuff.
In games the i5 is always
as fast or faster than the Phenom II (at stock speeds) and overclocks much better than the AMD chip.