Dance On A Volcano - no one can play those awesome hihat offbeats like the master Phil.
Yeah, you are right, but hearing Phil live (he's SOOOOOOOOOOOOOOOO much better live, in my opinion) sing "On your left, and on your right, crosses of green and crosses of blue... your friends didn't make it through! Oh OH! Oh Oh-o-oh!!" gives me shivers just thinking about it.
Perhaps a controversial pick but Shine On You Crazy Diamond by Pink Floyd. I just don't think the beauty of that song can be fully conveyed live.
This is quite right. Though if you're willing to go along for the ride, the versions played on the 2006 Gilmour solo tour (with Rick Wright) were good in their own right. They didn't achieve the epicness of the original 28 minute gem (these versions were about 12, 13 minutes long) but they were good in and of themselves.
For me: Anything other than Awaken from Going For The One. It's my favorite record, and live they just lose much of the delicateness and beauty of those studio tracks. I love love love Chris Squire, but he's a rock bassist, and Yes live is (was?) so much more heavy than on record, and what makes GFTO special to me is the delicateness of that material.
Also, a lot of Ozzy Sabbath after Vol. 4. Some songs, like Spiral Architect (one of my favorite Sabbath songs) just need more than bludgeoning riffology, and it never translated live for me.