We have a couple of birthdays today (September 22nd), both actors only made the one appearence in the live action franchise but are well known from other series.
Up first is Jim Byrnes a musician and actor who is probably best known for his role on Highlander the Series playing the watcher confidant of Duncan Macleod. While his voice only makes a guest spot in the SG1 episode Heroes Part 2 he has a more meaty role doing voice work on Stargate Infinity. IMDB
Daniella Alonso played “Katana” in the Stargate Atlantis episode The Lost Tribe, she is currently starring in the new show Revolution but has also appeared in Covert Affairs and Friday Night Lights. IMDB