Always enjoy reading how someone has done a from scratch restore - particularly one of the old faithful bikes we all used to ride .... CRs, KXs, RMs, TMs, YZs etc. However I will read and re-read any and all articles about the bikes that were extra special - Roberts RH250, DrCosters RN370, Jeff Smiths BSA etc - especially if the article is about how they were developed etc.
Then again, what really gets my juices running is the bikes that I wanted to ride (apart from the works Suzukis) - Wheelsmith Maico, Franks Honda, FMF CR125, Rickman Montessa, DG YZs etc. Hell, I enjoy any decent in-depth article that shows the passion of the builder/owner/restorer.