I don't normally do outbound email due to Canadian anti-spam legislation, but when I do send an email response regarding a domain I normally use the email address that is the registration Whois email address. I have used that email for many (12 or so) years since I have owned the associated domain.
I do normally also list an email associated with my much more recent domain name website (
www.namesthat.win), just so they can make the association and perhaps go have a look at what I have available in other options beyond the one they asked about.
Although I have a generic info@ email associated with both websites, I never use that as the return email when I am responding to a query, but rather one that uses the normal first letter, last name email name with the domain. To me it just looks more personal and professional.
I would not personally use a hotmail or yahoo email for domain name sales, but would use a gmail email address, but that may just be my own bias.
I agree with those who posted about the importance of the link with the Whois email to establish authenticity that you for sure are the real owner of the domain name in question.
Bob