OK, I have already built one knoppmyth box back with a release from about 18 months ago. Old school computer, nothing fancy. I had to get a Hauppauge 350 because I needed the TV-Out.

Here is what I have for my new box.

Computer:
Dell 8400
SATA (I know this is a problem, I am going to find a ATA drive just for the OS)
P4 with HyperThreading
4 Gigs of RAM (is this overkill)
GigE
nVidia Quadro FX (not sure which model yet)
I have a wireless G card that works with ndiswrapper, but I am going to go wired because the speed difference is so huge, and wiring is not a problem.

Tuners
Hope to still use my 350 for at least in probably not out
probably a Hauppauge 150. I am still researching.
I could probably get away with a bt8x8 card because I have such a fast computer with tons of ram.

Anticipated Problems.
I live in NYC, this means Time Warner Cable and maybe a cable box.
Roommates.
SATA (might have a solution)

Any pointers would be a huge help. Anyone have any experience with a Knoppmyth box in NYC.