Joe Flanigan (John Sheppard), David Hewlett (Rodney McKay), Rachel Luttrell (Teyla Emmagan), Paul McGillion (Carson Beckett), Amanda Tapping (Samantha Carter), David Nykl (Radek Zelenka), Chuck Campbell (Chuck) and Gary Jones (Walter Harriman) are the only actors to appear in all five seasons. Of these, only Nykl, Campbell and Jones were never regular cast members on the series.
Dr. Rodney McKay:
Have you seen my complexion?
Teyla Emmagan: Yes.
Dr. Rodney McKay: Yes, it's very fair. Extremely fair... This isn't fair.
Elizabeth Weir is supposed to be an American, yet pronounces everything the way that a Canadian would.
This is most noticeable with the word "been" which she overemphasizes in a manner that an American English speaker would not.