If your receiver is sophisticated enough to let you pass-thru component video signals, then it probably has optical or coaxial digital audio inputs. I would use those.... however, if your DVD player has discrete analog outputs for all your channels (like my Oppo HD971) and your receiver can take these through something like a "bypass" mode (different receivers have different names), you might want to connect your DVD using those. Most DVD players that offer discrete analog outputs also have volume control. The advantages are as tfm75 explained and, if this means that your DVD player is SACD or DVD-A capable, then that is the only way to truly enjoy those formats. Keep in mind that you will be bypassing your receiver's DACs in this configuration.
From your post, I am not sure where your TV sound will be originating from. If it is coming from a digital source (i.e a digital cable box), then I would use that connection and not the TV's RCA outputs, especially if a coax or optical output is available. If you don't have a set top box and you are using your TV's tuner to handle your cable signal, then I guess your TV's output is your only choice, which means probably mono, stereo, or downmixed stereo at best. On the plus side, if that's what you have, it means that your TV probably has a built-in HDTV tuner. I don't know where you live, but where I live I get about 14-16 HDTV channels over the air. All you need is a fairly inexpensive antenna. I paid $100 for mine but you can get one for as low as around $20.