.+@.+(\..+)?

should satisfy you both right? I use the original or a form of usually when I had to check emails.

That's identical to just doing .+@.+

Fully qualified domains actually end in a . If you're allowing sally@google then you must also allow sally@google. To be valid

No you don't. Email addresses explicitly require any periods in the domain to have at least one (non-period) character after the period. From RFC 5322, the relevant grammar production for the domain looks like

  dot-atom-text   =   1*atext *("." 1*atext)

(where atext is letters, digits, or a set of specific punctuation characters that doesn't include periods).

Ah, I wasn't aware that email addresses defined that differently. it looks like it's also the same way as part of obs-domain as defined by the addr-spec part of that. RFC 822 also seems to say the same thing, it's been way too long since i've tried to read those RFCs.