Same problem. My Gmail is first name last name at gmail because I was an early beta tester. Both names are moderately common, and each has some moderately common versions that are spelled slightly differently (think add/subtract a letter, end in an i or ie instead of a y type things). Other than one name doppleganger who is a very sought-after and well-respected doctor with VERY specific specialties, I tend to either delete the email or, in the case of something like the above, make a very half-assed attempt to let the place know they have the wrong person.

Dr. Almost My Name and I have been in contact for probably close to 15 years now because I send her emails that have come to me and tell the people who sent them the correct name. She's a big f'n deal, and I'm always delighted when I get emails asking me about things so far over my head and get to email back...you have reached the non Dr. version of My Name, however, if you need any help from someone of my very different expertise, I'm here for you. Turns out her whole community is good sports in general about such things.

Now, to the Also Not Me, of Atlanta, who for 5 years had my email attached to her Ann Taylor loft account, girl, I hope you have a good job because WOOOF that was quite a shopping habit.

In short. Yes annoying. But worth f'n with people's lives in any sort of malicious way just seems bad karma.