This question comes up a lot, so I'll try to address it here. There are a number of things this question can really be asking, and it may be asking more than one of those things. If I miss something then post a reply and I'll update this original response.

You're wondering if you should build your own computer. By that do you mean "is it practical"? The short answer is that you will save money and end up with a better computer if you build your own. And you will learn a lot by building it yourself. But you will have to provide the labor and technical support. So there are tradeoffs.

To me, the main reason to build your own computer is because you have the desire to do so. It will be something enjoyable to do. When it's done, you'll have the satisfaction of knowing everything about your computer. As a bonus, you'll save money, too.

If by asking "should I build my own computer" you mean "do I have the skills to do it?", my opinion is that anyone who has the desire to build their own computer will be able to do it. You can look over my assembly instructions and see what you think.
http://www.mysuperpc.com/build/pc_parts_list.shtml