Now my system totals are 247W. Thats using the max numbers in the link. Assuming all my components are using the full 247W, I should really be using a 350W PSU. This allows the PSU to run at 70% or less, which is recommended for PSU life. I figure however, that if I'm already erring on the side of caution, I can take off 5W for each item I guessed at. This takes me to 205W which lets me use a 300W PSU happily.
Thanks for the advice, everyone! Camie, you might have noticed in my CPU fan thread that my machine is going to be really really close to what you've got - so I guess that means I'll be safe with a 300 watt PSU. I'm thinking that I'm going to go with that one, since I'll have to order a couple of silentdrives anyway (and can hopefully save on shipping). Thanks!