I would recommend that you get a 400w power supply instead of your 300w. Eventhought your system specs would be enough for a 300w to handle it, I would hate for you to get mysterious crashes due to a 300w not handling the powerload of the AMD XP1700. Also, getting a 400w would be good for the future, as you can upgrade without worrying about your PS. Just a thought.
Besides that, your specs look great.
-Colt