I just finished reading Old Mans War and The Ghost Brigades, both by John Scalzi. They are set in the same universe, and loosely connected, although the plot of each is very different.
Old Man's War won an award for 2005, and is outstanding. The Ghost Brigades is just as good. I can't properly review them, but I suggest you check some of the reviews on Amazon, or other places. I freely admit that they were probably the best sci-fi books I have read in a long, long time.
Dave