Keep in mind that this is not over though.
1. Eastern and Southern Ukraine are going to be the real issue in the near future. Because the Russians can not afford to lose Ukraine and by taking Crimea, they effectively cede Ukraine to western influence unless they take further steps to partition Ukraine. Ukrainian elections in the last decades have all been close affairs, of the 55-45 kind, and if you take away the most pro-Russian part of the country, you irreversibly lose the ability to control the whole country through the electoral process. So I don't see this stopping here. But partitioning the rest will be a much uglier process than annexing Crimea.
2. In the long term, there will be a real war between Russia and the West, it's almost inevitable. Russia is the one state that will remain in possession of large amounts of fertile land, fossil fuels and other natural resources, even after Peak Oil and climate change have started to seriously wreak havoc in most of the rest of the world. Yes, they will lose the southern steppes to desertification, but Southern Siberia will open up to agriculture so there will not be much net loss. Meanwhile everything south of Iowa will have turned into a dust bowl, and good portions of Southern Europe will look like Libya today. There will be a lot of appetite for that territory from a western direction (and from a southeastern too - imagine a billion and a half hungry Chinese and a Northeast Siberia with a total population of 5 million or so...). So the Russians will have to defend it again, sooner or later. Once you see it from that perspective, you can understand why they had no choice but to draw the line and stop the encirclement here.