Re: Transformers comics
The old Marvel UK stories were awesome. I Know IDW are planning on reprinting the old Dinobot stories which were really good and they recently reprinted the Target 2006 story.
Also the new IDW Gen 1 stories are a whole new take on the story so would be a good run to get on board with.
If you want more of the Movie stories then they have done a prequal and plan on doing more stories as well.