Dell bought out Alienware in 2006 but nothing really changed with the Dell line up or the Alienware line up. Dell XPS gaming line was somewhat in direct competition with Alienware desktop PCs over the past two years, but now Dell has cut their Dell XPS gaming line up, it will continue as a high end line but they will dedicate for the first time the Dell R&D to work with Alienware to make better machines. The result of this work will most probably be showing up next year, it will be interesting for sure.
Link: Crave