ye you should be fine the 4300 will be marginally quicker as it has more bandwith, but to put your mind at rest, check what your mobo supports, i.e Ram voltage, dual channel (if your runnin 2 sticks). then check your Ram matches the mobo.
I recently built 1 for mi dad; Asus p5wdh deluxe mobo, 2 gig corsair xms pro, E6700 core duo cpu, 150gb wd Raptor hd.
I have one similar and they are quite nippy, but depends what your budget is.