Star Trek: Invasion Series

First Strike - Diane Carey The Soldiers of Fear (Star Trek: The Next Generation, #41) - Dean Wesley Smith, Kristine Kathryn Rusch Time's Enemy - L.A. Graf The Final Fury (Star Trek: Voyager, No 9: Invasion Book No 4) - Dafydd ab Hugh

I found this cross-series collection of novels all dealing with the same enemy but in different ways, in different times and sections of space to be an interesting concept.  The separate novels were entertaining and fairly well-written for this type of novel.