Ive always been an intel/nvidia fan. Im not all about having the best but i like to perform well. Right now Im on a Pentium D. I personally like my intel build by its overall looks and the parts performance. I am aware the 955 out performs the Q8400.
The AMD build is stronger, in processing and graphics power. The 5870 performs similarly to a GTX295, and a 955 performs similarly to a Q9550. Its not really even a competition if they come out similarly in price.