I played a lot of Diablo. I played a lot of Diablo 2. Before them, I played plenty of dungeon crawls, from Nethack to many DikuMUDs. After Diablo, I played a ton of Neverwinter Nights and Infinity Engine games.
Playing alone, these slowly became experiences on the level of "I'm bored, I'll kill some things."
Playing with friends, it becomes "Lets kill things together.", and so much more compelling. I won't bring up the cheating issue, since the only solution to it was being picky about who you played with (which I was).
I like multiplayer crawls and RPGs, despite the fact I despise MMOs (the only way to exclude the people you don't want to play with is to find another MMO).
The biggest question is whether or not Blizzard will let me play with others without a monthly fee. What motivation do they have, when it can only compete with their very own market leader, WOW? If there is no fee, will they inject inappropriate advertising, bundling, or branding (equip this sword by emailing your cable company to get G4 on the basic digital package)?
If they do, great; my friends and I will have a blast with it. If fees or other annoyances enter the equation for multiplayer, it sounds like this will be a readily disposable single player experience.
Also, if Blizzard is more or less the richest studio in PC gaming, I bet they could afford to let me download their trailers directly, without the bittorrent.
EDIT: If Warden is required by this, the discs won't get within a mile of my box.