Out of Pod Experience

Its seems ethnic russians are not the majority there. Ukranians and a lot of native muslims (who hate russia because of stalin). So it seems most dont want to be in russia.

Yup.

Outside of Sevastopol, the only other western warm water port for Russia is Syria's Tartus, which cannot service its large ships.

Ukraine was a big chunk of Russia, prior to the breakup. Given its economic woes (largely created by the kleptocracy of its former gov't), have the eastern side of Ukraine (rather, some percentage of the population) agitating for rejoining Russia.
So it is in Russia's strategic interests to annex the Crimea, at the very least. Will they take the whole country is the larger question.

And as stated, NATO will not get involved in a war with a country that can actually shoot back. It also makes the Euro's decision about this invasion a lot easier when one looks at how much of Russian oil heats Europe and fires their economy.

Ukraine is mobilising...

Well, since this, strangely, isn't getting locked, I'm going to throw in my own two cents.

To me, this looks like it's simply a grab for land and power. There are some potentially legitimate concerns about protecting the people of Crimea, but if that was Putin's true reason he would've gone about things differently, probably seeking multilateral support for the mission. Instead, Mr. Ex-KGB has basically invaded a sovereign country in an effort to secure another chunk of the former U.S.S.R.

The other part to this is that NATO nations are signatories of a treaty to ensure the Ukraine's security. Putin knows this, but doesn't think that NATO has the testicular fortitude to follow its treaty obligations and stand up to his forces. He probably figures that the U.S. would normally act even so, but after ten years of conflict in the Middle East, Americans are tired of the cost of war, both in human lives and dollars. As such, he probably feels that all that will happen is sternly-worded warnings and little else. I think he's so confident of this that he doesn't expect to see actual troops on the ground.

Personally, what I'd like to see is a multinational force moved in--only with the Ukranian government's permission!--to the areas of Ukraine that Russia has not yet occupied, but no direct assault on Russian forces unless they attempt to seize more of the country. The presence of troops that he doesn't expect to see would hopefully cause him to reconsider his plans and bring him to the negotiating table so that a peaceful solution could be worked out. And, if he's prepared to try to take the rest of Ukraine despite the presence of Western troops, then he'll have proven that the Russian government has become nothing more than avaricious criminals and despots.

Don't you mean the world? ... oh wait, they need to kill off or subjugate 1 bil Chinese before that happens

Stay away from Russian borders!
We won't accept regime change at our borders. We will fight back.
Enough is enough!

I bet Ukraine regrets getting rid of its mobile nukes now.

Incidently, the nation just happens to own the best urainium mines in the world.

Yup, like I said, there are about 6 reasons that North Korea has not been invaded.