The official Doctor Who website has confirmed the return of the Sontarans for Series Four. This is very cool news.
Forget the Daleks and the Cybermen - I've always been a slave to the Sontarans. It's a peculiar love because they only ever appeared in four stories and only one of those stories deserves the label of great: "The Time Warrior", which was also their introductory story, as well as being the tale that introduced a certain Sarah Jane Smith. (Although I do have a great deal of affection for the flawed yet entertaining "The Two Doctors", which marked the Sontarans final screen appearance.)
The thing I always liked about the Sontarans was that unlike the pepperpots and silver beasties, they had personality (mildly odd for a race of clone warriors). They were always pissed off and defending their honor. As with all of the returning baddies to the new series, I'm sure RTD & his cohorts have something revisionist in mind for these guys, but hopefully they retain their Grimace-like look alongside their inherent pissed-offness. They're off to an interesting start with the casting of Christopher Ryan as the Sontaran leader. Most cool people remember Ryan as Mike from The Young Ones.
Me? Not so much because I'm so uncool and was never a big Young Ones fan. He always amused me most as Marshall, Edina's first husband in Absolutely Fabulous, who was always hopelessly clueless and endlessly chasing some nebulous Hollywood deal. Ryan's an odd choice for this part since he's mostly thought of as a comic talent, but I look forward to seeing what he's gonna do with it. It says a lot that they've cast an "actor" rather than a guy to fit inside a costume.