Is it proper etiquette to email a thank you note?

Although I am sure that I would disappoint my late mother in too many ways to count, she would be pleased to know that I still send thank you notes. Recently, an old neighbor (pre-divorce)invited me and my girlfriend to their house for dinner. Nice couple, great food and wine, nice house. I would normally write and mail a thank you note. But then I wondered…Have the etiquette standards changed with the times. Is it OK to send a thank you note by email? I am a little hung up on the idea that it is not hand written. There seems to be something slightly impersonal about it. But then again, my penmanship is atrocious. Seriously though, is it accepted etiquette to send a thank you email?