I have purchased Batman: Arkham Asylum 4 seperate times. First was the collectors edition for PS3, I traded that in. Later bought the regular PS3 version when I felt like playing it again and ended up giving it to my brother. I then bought it for Xbox for the achievements. Finally I bought the GOTY edition for PC.
I've also bought the GOTY edition of Oblivion, Fallout 3, Fallout: New Vegas, Batman: Arkham City, and Borderlands on the PC when I had the regular version on console, some of which I had all the DLC for already. Though I usually picked up the GOTY version during a steam sale or something.
I agree that digital is the future, but for now, people want the disc's. I think It could go one of two ways. Either Microsoft changes policies or Sony does. Microsoft's policies lean towards favoring the publishers, allowing them to get the sale they would have lost to a used game. While Sony favors the players, letting them trade, share, and sell all they want. Microsoft might get exclusives because of its policies, which could bring a larger audience seeking those games. Sony could get the larger audience, meaning publishers would go to them to reach that audience.
And really, Sony has DRM in place. It's called the disc. You really think they will let people install a game and play it without the disc (which is the only reason Xbox has its online checks) without some form of control. That would be crazy and they would get so much flak from publishers for it. And downloaded games will probably be locked to the account's main console without an internet connection.
I could see Microsoft getting rid of the online checks but only if they remove the "play without the disc" feature, which I like, and locking content to the purchasing console without internet connection.
Bioshock would be up there on my list. The reveal in that game blew my mind. I would say KOTOR as my first playthrough was ruined by a corrupt save, but I had made it to the twist and replaying the early parts knowing who you were the whole time was probably my favorite part of that game. Maybe Call of Duty 4, but only if I could erase all knowledge of every modern shooter that followed it before I did so. I think it would be a tough choice between Bioshock and Portal for me. Both were great first time experiences that had diminishing returns with every following playthrough.
Binary Domain is the most recent one I can think of. I loved the game. Thought the characters, dialog, and game mechanics were really well done. It's a solid third person shooter that adds a few twists of its own to make it fun and interesting.
GTA V wouldn't really be a reveal, so I don't think it would be that. Valve has steam to announce their games, but he did say it was "part" of a world wide reveal, so maybe. Respawn's game is possible, EA would love the good press as we exit the summer dead zone. Blizzard is unlikely to announce anything before the Starcraft and WOW expansion are out, but it could be the games release dates, or a Diablo expansion. On the other hand, this is too close to GamesCom for this not to be related, and I doubt Blizzard would announce anything major outside of BlizzCon. Bungie's game is possible, unless Activision doesn't want to overshadow Black Ops II. Come to think of it, the reveal is probably just the "reveal" of the Black Ops II multiplayer, they haven't showed anything on it yet to my knowledge and they always use the term "reveal" even though it's they same thing each year with minor changes here and there. My bet is it's just a "Multiplayer Reveal" trailer that hits that day, though I would love to see Gordon Freeman on the cover, crowbar in hand, proving me wrong.