Basically, P (replaced the old W/A/G series) - Workstation class. Beefier CPUs, and often a discrete GPU. Tend to be heavier and run hot. So more of a desktop replacement for engineers/scientists/etc. T series - General purpose higher end business laptops. Various options in terms of CPU etc. X series - Ultraportable. Smaller screens than the T series and sometimes has low power CPU options, but can have fairly beefy ones too. Useful for people who have to work on trains/planes etc... X1 - The fanciest thinnest ultraportable. E/L series (replaced the old R / I series) - Basically cheaper laptops for businesses/students who can't afford a T series More on reddit.com

The T and X series have roll cages which make them better suited (structurally speaking) to withstand falls and general abuse; The E and L are very similar but they don't have roll cages. I believe that the E and L are also heavier, really not designed to be carried with you all the time? As I'm sure you're aware, ThinkPads are mostly business laptops and I believe the E and L series were born out of the necessity of some businesses to save money not by reducing performance but rather, protection that would go underutilized on a laptop that sits mostly on a desk. More on reddit.com

E - Budget L - Budget plus T - Business work horse P - T series but with quadro options X - Lighter T X1 - Flagship Yoga - Flexiboys Z - Garbage More on reddit.com

As we find new laptop release please share them here and I'll add to the list. More on reddit.com