For the first four months of 2010, thus far, the best selling Dell notebook computer is the Dell XPS Laptop with a 16" screen. Featuring 1080p HD, the basic model comes with a Intel i7 core processor. Dell assembles its computers from huge lots of parts acquired in close outs by manufacturers who are moving on to the next-next thing. Dell cobbles notebooks together to create one model and another and then offers them for sale. When the line is exhausted, it is no longer available and another new and better product comes along. If you get a print catalog from Dell hang on to it and compare it to another one three months down the road. The offerings are completely different. Dell does not maintain a particular model for very long, so it is not possible to say that there is a "best selling" model or one that sells better than another from one week to the next.