If the people in the Crimea genuinely want to secede from Ukraine and join Russia, then I say that's what they should do - it's not up to the Russian, Ukrainian, EU, or US governments. The problem is that no government nor media on any side of the equation is actually interested in the facts of the situation.
The current "Crimean Parliament" is a band of hired thugs that forcibly expelled the elected Crimean Parliament two weeks ago and that will vote whichever way Putin tells them; their decisions aren't worth what my cat leaves in his litter box. All the Western media reported this forcible takeover of the Crimean Parliament as shocking when it happened, now they're reporting on the votes of the "Crimean Parliament" as if they're legitimate. WTF? That expelled elected Parliament was
moderately pro-Russian as well, but they were way too reasonable and responsive to the needs of their own constituency for Putin's liking - they would NEVER have allowed a Russian military invasion that claims to be a domestic militia. In light of that, I'm not convinced the majority of Crimeans actually want to join Russia. Putin's propaganda mills say they do, but these also insists the troops in the Crimea are "Ukrainian defense militia" as opposed to a Russian invasion - their claims are equally not worth cat droppings. The protests and marches indicate the existence of a pro-Russia sentiment, but to determine actual majorities requires polls and statistical research which are made impossible by the presence and intimidation of this same "mysterious" force. See how convenient that is?
A reasonable diplomatic solution for the West is to ostensibly refuse to allow Putin's lies to be treated as reality, impose massive sanctions, and not budge. It's an economic war of attrition and the EU has far more capacity to endure it than the isolated and underdeveloped Russia. Putin is unpopular to start with and his people have no democratic way to get rid of him - give them a little more incentive to lynch him and they will do just that, with the ensuing division of the Russian Federation being quite beneficial for their competitors the EU long term. However, I see that the EU will continue to take Putin's bluffs seriously in fear of the short-term fallout on their own shaky economic structure. Cyprus, Greece and Italy are still there and it wouldn't take much for their economic patches to come off. As a result, they may try to decide the Ukraine's and Crimea's fates in a 'compromise' without the consent of the actual people there.
In this age of decentralized communication, such 'compromises' between superpowers usher in populist chaos on the ground where no one with a claim and a foreign curator can garner a critical mass of support - see Libya, Syria, CAR, Yemen, the Sudans, Egypt, Venezuela, Thailand, you get the point. Besides contributing to human rights abuses and economic instability, these crises also drain the resources and political credibility of foreign curator governments as they try to support their respective criminal puppets and install them as dictators. The size, relative transparency, and most importantly location of Ukraine will make this effect far more profound there than in the other countries on that list; spelling political disaster at home for the superpower governments. For the EU, this will mean electoral mutinies in the upcoming referendums by which sub-countries like Catalonia and Scotland secede from EU member States and compromise its foundation. For Russia it will mean old-fashioned popular riots that depose and violently dispose of the criminal KGB government. Despite what Putin's pet media claims, the millions in protest of his return to the Presidency in 2012 demonstrated that nobody likes him - a worsening of the political and economic situation will push that sentiment to critical mass.
I stick to my prediction that Putin's days are numbered regardless of what happens, and it seems he might take the multi-national Ponzi Scheme known as the EU with him by virtue of their proneness to cowardice - which only makes me happier. The US would be wise to return to our pre-WWI roots and maintain neutrality. There are no good guys and we should let the crooks and murderers eat each other, or we shall go down with them.