I haven't seen too many pics where you get to read the last thoughts, but the few I have were awesome!

Juan Gotoh's comics have a bunch and you can find them on exhentai. Graduation Beheading Ceremony, Applicant for Death, and my favorite Guillotine Masterbation have so great last thoughts scenes.

There's also a Chinese made 3D image set of a snuff and dolcett club where the main character is beheaded at the end and thinks "it's exciting being a meat girl" as her cum soaked head dies on the floor.