if you are going to overclock then an intel c2d 6600 (and maybe a 6400 with a good-sic moderately high- overclock) will pretty easily smoke that amd buddy.
if you are going to stay stock, (that's okay and all) and really want to go amd, get an x2 4200.
it's way cheaper than the 5200. it's actually (i think) the best dual core you can get for 150 bucks....maybe an opteron 165 is better, but only if you overclock. and if you are going to overclock, well...see above.
your ram is good, but i'd go with plain ol corsair xms ddr2-800.
i don't know how high that 5200 will o.c., but i will wager it won't be much (if at all) over 3.0ghz. of course at stock speeds that would put ddr2-800 at 500mhz, so you may be better of with ddr2-1066. that's expensive, though, as i am sure you have noticed.
everyone here seems to like the fortron psus. i think it's a 480W, but someone else knows for sure i bet.