if you want fairly good service if something breaks, buy a dell. If you know what you want or want to build / be responsible for your own machine then go through newegg or tiger. I work for the one I mentioned but really the only thing that makes my side of things different is I work directly with corporate IT departments, providing myself and my resources to them and do it better than Dell and tiger/newegg are a different business model as they dont really offer a dedicated rep.
Its all in what you want and need
But any of the new machines out there will do what you need unless you are doing a lot of video editing or gaming. Thats when the differences in machines start to matter.