actually NewWho has some good one off aliens, but when it comes to recurring aliens I think it is lacking in that departments, most of the best one off aliens just would not work a second time around.
the Sontarans have two books coming out, they have done quite well out of the new series.
I would love to see more of the Sycroax but it does not seem likely.
Yeah, the Weeping Angles from Blink were AWESOME creations (and one of the best ever seen in Who)... but they'd still be kinda hard to use more than once.