Dan Larkin suggested this (and you folks can feel free to make your suggestions for future Top Fives here), and I thought it seemed like a fun topic, so here goes!
5. Jimmy as Wolfman
This probably shouldn't be THAT high on the list, as it's a bit like one of those "cashing in on fads" transformations, but darnit, Jimmy looks really cool as a Wolfman, doesn't he?
4. Jimmy as bizarre alien-like creature.
You have to give it up just for the way Jimmy describes the transformation!
Jimmy's become an alien before (he became a Jovian) but never as wacky as an alien as this one!
3. Jimmy as Bizarro-Jimmy
Come on, it's Bizzaro-Jimmy! What's not to love about that?
2. Jimmy as Giant Turtle Boy
This was a tough one. You HAVE to love Giant Turtle Boy, as Giant Turtle Boy is such a bizarrely awesome idea. There really is only one possible transformation that could beat this one...
1. Jimmy as Elastic Lad
and it's Jimmy as Elastic Lad.
Elastic Lad might not be nearly as creative as Giant Turtle Boy, but it is probably the single most used transformation of Jimmy.
In addition, as Elastic Lad, Jimmy joined the Legion of Superheroes.
Also, as Elastic Lad, Jimmy was involved in the story that I have the cover above, which is one of my favorite Jimmy Olsen stories of all time, a story where we see just how good a friend Jimmy Olsen is to Superman (by the by, how weird is Superman's thought balloon on that cover?).
Those are my picks! Agree or disagree? Let me know! Thanks, Dan, for the topic!