Crusader, a notable recent set of stories about ``human colonization and the struggle of humanity to survive and war with with other alien races'' would be John Scalzi's:
Old Man's War
The Ghost Brigades
The Last Colony
Just finished reading _The Ghost Brigades_ and found it interesting (but irritatingly filled w/ typos).
Also, while it doesn't have colonization, Harry Turtledove's _Vilcabamba_ is a thought-provoking story of war w/ an alien race:
http://www.tor.com/stories/2010/02/vilcabamba
William