Haha, I never thought about this. (The only character I can remember ever fantasizing about playing is Luna Lovegood from HP, lol.) I've always thought Holly is my opposite in almost every way, so definitely not her. Juliet, same thing, being athletic, presumably somewhat taller (being a Butler) wouldn't be a good fit for me either. Opal, too pretty and sophisticated (I've never worn makeup, but I'm sure no matter what you did, I'd make it look weird XD!). Minerva's probably my closest personality fit, being the intellectual she is, but I can't imagine being her either. I can't really do accents, not to mention she's twelve...
I feel like for me, the best fit would be a non-entity character who only appears briefly. Like the waitress from En Fin, or Dr. Constance Lane's secretary. XD! (Or maybe a librarian, if there are any librarians in AF.)
“After all, absolutely no one can help but suspect a criminal, liar, and manipulator of committing crimes, lying, and manipulating. And of course, no one is more aware of that simple fact than Artemis Fowl.”
Opal sets into motion her most diabolical scheme yet, to frame Artemis and turn his closest friends against him. Only this time she has a new calculating partner who knows Artemis better than he knows himself. [An Artemis Fowl fanfiction, set after The Atlantic Complex.] https://www.fanfiction.net/s/8336552/1/Noble-Heart
...Shameless self-advertising, guys! C;
(And if you're really bored: http://axxonu.deviantart.com/gallery/28912232/Artemis-Fowl
AF fanart. ;J)