Only a crazy person would want war with Russia. The thing to ask ourselves, though, is whether Putin is crazy enough to want war with us? Probably not, but there is a disturbing surge of nationalism going on there now, so who knows for sure. I think if you see him go into eastern Ukraine, you can assume that he is a man that doesn't care much to be peaceful.
I do think Obama is acting in the right way. Beats me why he would say that military action is off the table in public, though. That's like showing your opponent that you only have a pair of twos when they have two pair before you've placed a bet. I also would have liked to see a more rapid and expansive approach to sanctions. Admittedly, the hesitation of the EU might be a factor in coordinating that kind of response quickly though. I get the impression based on our response so far that this administration hasn't yet embraced what I believe to be a naked fact, which is that Russia is playing hardball for keeps as it attempts to re-establish it's dominance over former satellite states, it isn't far from discarding it's facade of democracy, and won't stop short of brinksmanship.