Evelyn from “The Mummy”.
I, too, work in the historical field and I, too, get in incredibly bizarre accidents. Remember that scene where she knocks over all the bookshelves? While we were watching that, I felt a good deal of sympathy-- that’s the kind of shit that happens to me.
Jim Halpert from The Office, J.D. from Scrubs, a dash of Michael Bluth from Arrested Development, and a handful of Buffyverse characters for their traits and habits: Wesley, Giles, Angel, Xander, Willow, and even Spike on some days.
Janet Carter from Pamela Dean’s “Tam Lin”: a short, just-curvy-enough-not-to-be-skinny redhead English major with a slight superiority complex, ear for poetry and poetic prose, and extremely high relationship standards? Oh, yes. It’s a wonder either of us ever get more than two dates with the same person, if we haven’t scared them off already by throwing lines from “Henry VI” at them at them and seeing what sticks.
When I catch myself associating with Diana Villiers of O’Brian’s Aubrey/Maturin series, I know I need to change some things in my life. 
Pam Beesly from “The Office,” but only at my summer job (which is over, hooray!).
Shakespearean-wise: Helena from “All’s Well that Ends Well” and Julia from “Two Gents of Verona”: the object may be flawed, but they pursue it anyway. Not always a good thing. “My projects may deceive me/But my intents are fixed, and will not leave me.” And I associate in a wish-fulfillment way with Margaret of Anjou, at least in the first two halves of her quartet of plays.
My biggest fictional-character association, however, is with the lady from whom I took my username.
I’m nothing like the Rebecca from whom I borrowed a part of my username, but could very well be Max’s 2nd wife, blonde and small and nervous. I’d have buckled under Mrs. Danvers like a threadbare rug.
I’m totally Eleanor Vance in “The Haunting of Hill House”. Obsessed with the daydreams in my mind. Somewhat more extroverted, but still…daydreamy. And nervous.
Or definitely Anne Elliot in “Persuasion”. Passionate at heart but mostly letting the brain win all the internal arguments.
–Beck
Joel from Eternal Sunshine of the Spotless Mind…
“Why do I fall in love with every woman I see that pay’s the least bit of attention to me.”
I love his kindness, sadness, his way of reasoning, and hope, toward the small world of which he chooses to focus his life in…
I enjoy relating with him and makes me feel closer to him, but couldn’t say it were a definition…
It’s a nice gift, the ability to admire and carry the tiny complexities which make us up- Life is good.
In my younger days, I strongly identified with Brian Krakow from My So Called Life: I was always raising my hand in school and getting picked on, and I was judgmental about people who acted in ways I thought were dumb, ie, drinking, going to clubs, etc. I even looked a lot like him.
These days, I can’t really think of anyone… I guess maybe a bit of the title character from The 40 Year Old Virgin, although I’m neither.
Charlie Brown from Charles Schultz’s Peanuts.