Pineapple Express is put out by the Kush Brothers on the West Coast. They do not offer seeds anymore as the plants are clone only now. I haven't grown it or smoked it so can't give you more than that.
I could be wrong but I believe it is also called Medicine Man! I have some and its a decent grower with a nice smoke. My favorite? No, but I still have it growing and don't plan to stop growing it.
I am a writer and have my best success with sativas. C-99 is a winner as well as JTR. I am playing with a Purple Cheese and a Bubbleboy that seem to get me going also. Just make sure you review the work with a clear head. Not all of my "high" ideas look so good the next morning. LOL!