I don't think it was until Gmail that I finally got comfortable using my real name as an email address; prior to that I used nicknames, as I did with IM handles as well — it seemed like it wasn't de rigeur to use your real name. Plus, wasn't that a cool thing about the Internet when you first started — the allure of anonymity?
Then, I don't know, I got older, and the then-new Gmail encouraged you to use your first.last name, like a work email address, and it made so much sense. A job application looked better coming from a real name rather than "email@example.com" (not my old email address BTW, just a spirited example). It was that way with the advent of Facebook too; whereas MySpace was more anything goes, Facebook's feel and UI are more straightforward than its predecessor.
But I haven't gone totally real name on the Internet; when I register to use a service or comment on a new website, I generally stick to my first name, or some variant thereof.
What about you?