This is pretty darn mind blowing because, to the best of my recollection, no other project has got this much money this fast. When Double Fine said they were going to make a fan-funded adventure game, they pulled in money at a decent clip, but certainly not at this pace. I'm not even sure that the Ouya had this much support out of the gates. So, it's certainly fair to say that there has been a lot of pent up demand for this kind of game for quite some time judging by the overwhelming support that it has received so far.
I'm definitely jazzed about the project, as games like Fallout, Planescape: Torment, and Icewind Dale are some of my favorite RPGs. The combat is pretty great, and it's been years since we've seen it done this well. The Dragon Age games sort of did it, but I still find the old Infinity Engine games a lot better for it, not to mention that they usually had a lot better storytelling, and a more interesting world to explore.
There isn't a whole lot to go on yet as to what we can expect from the game. We do know it'll be in a fantasy world with plenty of magic, and the big thing is the emphasis on this whole old school RPG experience. It also sounds like Obsidian wants to explore far more mature themes than they'd otherwise be able to if they'd gone with a traditional publisher. Often times when I hear developers say they want to do something like this I'm extremely skeptical because they talk big about this before the game comes out, and it turns out that the game's story isn't very mature at all outside of a liberal smattering of gory deaths and boobies. However, given the people involved with this project (Chris Avellone, Tim Cain, and Josh Sawyer), and their RPG track record, this is one of the few games out there where I'm willing to believe that they will do good job of exploring mature themes in a game. (The other company I trust for this sort of thing is CD Projekt)
Obsidian has already announced some of their stretch bonuses for the game now that they've hit their funding goal. Some of the goodies that they plan to add, depending on how much money they can bring in, includes new playable races, classes, and companions, housing for your characters, as well as a Mac and Linux version of the game. After that, who knows? It would be cool to see a toolkit added for mods, though. =)
About the only concern I have for the game is that Obsidian has a bit of a reputation for putting out buggy products that need to get patched up after release. Hopefully with this game they'll take their time, and make sure to avoid such problems. I'd very much like to see the game succeed spectacularly because, bugs not withstanding, Obsidian, and before that Black Isle, have made some of my favorite RPGs ever. They've also been screwed over pretty hard by big publishers in recent years, being forced to lay off staff because they didn't hit absurd Metacritc aggregate critic scores, so it would be great to see the company find a way to permanently remove their heads from the yoke of traditional game publishing. =)