There's not a rim brake out there that will match an Avid disc, but a 203 is a bit of overkill, especially hydro. Unless you're a clyde, stay with 160 up front. I roll 185 BB7's on my ride, and I have an FS/AM that carries my 235-240.
If you trust a carbon fork, go for it; I'm looking at the Instigator fork for my upcoming SS build.