COD2 was a classic (my favourite still).
COD3 was terrible
COD4 was again good but went from WW2 to modern day (i prefer WW2)... although was trying to be a bit over complicated for what it was.
COD5... yes it has the graphics but for me its got all that was not right with COD4 plus COD3. In essence... terrible.
Was expecting better. Its COD3 with better graphics in my opinion.
Bring on COD6 (from the people who made COD2 and COD4).
P.S.: Want a good shoot'em up on-line for Xmas? Get GOW2 or Unreal Tournament 3