Those who prefer to type “email” have noted that:
-It’s faster to type.
-It’s becoming the more “cyber-savvy” term.

Those who prefer to type “e-mail” have noted that:
-The hyphen serves as a reminder of the word “electronic” when typing “e-mail.”
-The hyphen indicates the correct pronunciation of “e-mail” (“eemail”) better than without.

Other very sound views of the issue have been laid out for us, ranging from Wikipedia references to “because I say so!” Although I myself can type either version of the word at hand without problem, I have a few observations myself.

Even though it is faster to type “email,” the time difference is probably in the range of 1 to .009 seconds (approximately ). In the case that someone’s life or well-being is hinging on how fast that word can be typed, I hope that those who side with the “e-mail” version can have the adaptability to type “email”…if just that one time. Plus the people who type “email” will have about 34 extra seconds of free time banked up by the end of the year versus the people who type “e-mail” because of the time-consuming hyphen. So I suppose if you’re busy–and could use the half-minute vacation time–then go with “email.” But seriously, when you consider writing by hand or texting, the time difference is more salient.

However, I can understand the point that was made regarding the “electronic” in “e-mail” that is underscored a little more with the hyphen. Because if the trend to shorten the word continues, we’ll just be saying “e” before you know it (lol). But for all the typists out there who are concerned with speed, what about non-letter keys? I mean, we’re pros at typing using the alphabet, but what about using the “]” key, or the “~” key? Personally, I want to sharpen my muscle memory for the hyphen key as well as the other non-letter keys, and what better way to practice that then using the hyphen in “e-mail?”

To answer the question at hand, I do use the hyphen…when I’m not at gunpoint. Yet I can see myself shifting to the non-hyphen version if the overwhelming majority of people use “email,” because I sure hope I can be adaptable in this one area of my life. lol

On this comment form I have to put my “email” address, and I can be notified of replies via “e-mail”.

I prefer email.

In the UK and Australia, the unhyphenated versions are used:
email/ online

Yet, from what I’ve noticed here in North America, they use:
e-mail/ on-line

Perhaps change takes longer to implement in larger populated regions and so the old hyphenated versions are still used here…?