There is an interesting thread going on right now on the yahoo XP group - XP and Scrum. Before introduced to a real agile project, I had read up on Scrum and it made a lot of sense at the time, but I certainly did not understand it. I suspect it's possible to figure out what agility actually means by reading about it - but for many, including me, I had to experience it before I 'got it'.
Both approaches use what I like to think of as common sense - but common sense is actually a misnomer, its not that common. They share many ideals, but the real difference is in the XP technical practices. For me, this is absolutely key. I believe that many of the failings of the numerous practices and methodologies out there are due to the lack of column space dedicated to great techniques to apply to programming. Usually methods specify what documents and pictures should be created and who needs to sign them off - but on many occasions these artifacts can be viewed as waste. As Kent Beck puts it, testing, programming, listening and designing - thats all there is to it - anything else and someone is trying to sell you something.
So, by no means do I view Scrum as a bad thing, but I do think that you stand a better chance of success by following the XP alone rather than Scrum alone - which is purposely vague when it comes down to programming.
Of course, the point is moot, because you don't have to adopt a single approach, you can have both.