Quote Originally Posted by Animeniax
The correct form for "e-mail" is with the hyphen, which denotes it's roots as an abbreviation of "electronic-mail", so any usage rules that apply to "mail" apply to "e-mail" as well.

E-mail has evolved, so it's ok these days to say "I'm going to send you an email." Whether that usage is appropriate or not doesn't seem to matter to your average user at this point.

In counter-point to your example, I've rarely ever heard "check your emails." People say "check your email", so it seems they apply the usage rules willy-nilly, at times treating it the same as "mail", and at times treating it like a special computer jargon word with its own rules.
It doesn't matter wether it's e-mail, electronic-mail, or email... these words are not exclusively mass nouns as the word mail is. The reason being that you can actually count units of e-mail as you would count letters (you can't count mail as units).

Let me put you similar examples. Beer and water are both mass nouns, you would say "I'm going to drink water" or "I'm going to drink beer". But just the same you can say "I want four waters and four beers" because in this case you're reffering to bottles of water/beer, units you can count.

Just the same you can count the number of e-mails and just the same you can use e-mail to mean the collective at the discretion of the speaker.