How should I connect my PS3 and cable box to get proper surround sound?

I would hook the dvd and the ps3 to the tv with hdmi. send an optical from the ps3 to the dvd/receiver.

use component for the cable box and send an rca to the receiver (if it has the input, otherwise the tv). Dvi-Hdmi doesn't send audio. You'll have to refer to your tvs owners manual as to how to input sound. some tvs have a slot for it right buy the HDMI, however my LG didn't. had some stupid headphone jack...meant for pc.

I wouldn't be too concerned with getting high quality cables for your HD box because cable doesn't brodcast in 1080p. There are a very small amount of ppv channels that do, but the majority doesn't and probably won't for awhile. But if budget isn't a concern, better quality never hurts.

In the end, I'd concentrate more on getting the ps3 and dvd hooked up with surround sound because they'll utilize it way more than an HDbox

Here's another example of why HTIBs suck--teriible connection options.

DVI is video only. Send your video from the cable to the TV directly using DVI and send the audio via optical to the "receiver". Then send the audio and video from the PS3 to the receiver via HDMI. You'll have to then forward the video to the TV with another HDMI.

That's the only way I see you getting surround sound out of both your PS3 and the cable.

You could put your 1 of your connections using componet cables (r,g,b) or buy an HDMI splitter (2 n 1) :)

Anyone that has enough inputs. Just make sure what cables will be running to the reciever and just make sure it has enough inputs for all components.