Some of you guys have no sense of economics. Why buy both? It makes no sense at all from a financial standpoint on your part. If you plan on getting both, granted we all have a little, "cirminal" in all of us, I'd suggest buying a good pirate copy to tie you over until 3.1 comes out, instead of forking over roughly 30 bucks in total on a movie that most of you find dissapointing anyway. Come on chaps, think. Save your self some cash.
As for me, I'm not going to bother with 3.1 because just like 2.1 it'll be up on youtube, where I can see it where ever I want. I'm happy with sm3 and thats the copy I'm going to buy, my first ever bough spidey film with my own money, its a glorious feeling.