7. Katee Sackhoff
Its not just Brits who have taken guest roles in Doctor Who of late. Theyve also cast performers from other countries with a track record in sci-fi and fantasy, notably Ben Browder of Farscape fame in the Series 7 episode A Town Called Mercy. For a while there was speculation about whether this trend was going to continue every series, which would no doubt be popular with those in other sci-fi fandoms. While that didnt really happen, Katee Sackhoff would suitably follow in this vein. Shes well known for her role as Kara Starbuck Thrace in the Battlestar Galactica remake in which she played the volatile-but-brilliant pilot with no small amount of charm. Her character instantly resonated with viewers, so much so that she became a firm fan favourite, suggesting shed be able to do the same in a role on Doctor Who, too. The experience in another sci-fi show might also help, as shed be comfortable in the quarries, warehouses and corridors that the Who team dress up as spaceships and alien worlds. Shed also be able to make them believable to boot. Shes popular at conventions, too, and often takes time out to connect with fans, another plus with a fandom that's as enthusiastic as this one.