Hi. I'd suggest connecting the PS3 and DirecTV box to the TV using HDMI for the best video connection. I would also suggest connecting the optical outputs from the PS3 and DirecTV box directly to the Sony STR-DE997 for the best audio connection.
If you only connect the PS3 and the DirecTV box to the TV using HDMI, and then connect the optical audio output from the TV to the Sony receiver, you'll only get two-channel sound. That's because the Samsung downconverts any sound coming in through an HDMI port into two-channel audio for output through the optical audio output port.
Alternatively, you could route the audio and video through the receiver using optical audio connections and component video connections (like you mentioned), but I think that the HDMI video connections will be better. You could always try both and see if you can tell a difference.