IMO, SP gaming with a console is boring. It just doesn't feel right. That's maybe because I'm so used to playing console party games.
XBOX Live cannot replace PC internet gaming. It's not free. Something that costs a monthly fee will not beat something that's free.
I love SP and MP gaming with a PC but nothing beats a console in a party. Nothing.
Getting a gang together to play a soccer, hockey, fighting or DDR game is a whole lot of fun.