If you type: 'Who was to blame for the Cold War' into google, what you mainly turn up is dozens of online essays of dubious quality, many of which simply rehash what you have already learned from my website! My strong advice is to avoid them like the plague, and make up your own mind.
By far the best link on this topic (and the liveliest) , if you haven't already found it, is the BBC audio-byte, which takes the form of a debate (you can read a transcript of the debate here). There is also a pretty shoddy list of points-for and points-against on the projectgcse website, which you may find of help if you have been asked to write the essay (which will have to take the form of 'on-the-one-hand ... on-the-other ... conclusion).
In the end, this is a subject where you will also have to show that you are aware of the historiography - what past historians have written on the subject. There is a simple summary of this on the BBC Bitesize site, and my more detailed account here.
So - what do YOU think!! As the BBC audio-byte demonstrates, this is a contentious and controversial subject, so you ought to be able to have some fun debating it here...