Wisely, Intel has decided to simplify their overly complex brand structure by boiling things down into three main categories: "entry-level (Intel Core i3), mid-level (Intel Core i5), and high-level (Intel Core i7)."
Intel spokesman Bill Calder notes:
...we are focusing our strategy around a primary 'hero' client brand which is Intel® Core™. Today the Intel Core brand has a mind boggling array of derivatives (such as Core™2 Duo and Core 2 Quad, etc). Over time those will go away and in its place will be a simplified family of Core processors spanning multiple levels: Intel® Core™ i3 processor, Intel® Core™ i5 processor, and Intel® Core™ i7 processors. Core i3 and Core i5 are new modifiers and join the previously announced Intel Core i7 to round out the family structure. It is important to note that these are not brands but modifiers to the Intel Core brand that signal different features and benefits. For example, upcoming processors such as Lynnfield (desktop) will carry the Intel Core brand, but will be available as either Intel Core i5 or Intel Core i7 depending upon the feature set and capability. Clarksfield (mobile) will have the Intel Core i7 name.
Pentium, Celeron and Atom aren't going anywhere, but for their premium Core brand, chips will be broken down into the three categories above. Calder also stated that this transition will take time—and probably won't be implemented fully until sometime in 2010. [Intel via ecoustics]