You are going to lose the shortcuts in the start menu of course. But, you can copy them back.
Many games place saved games in the "My Documents" folder. In my case, the "My Documents" folder is also on D. So, I have no problem with the save games. You should back those up before reformat.
I play some first-person shooters (Thief, Hitman, Iron Storm, Half-Life, Counter Strike, Half-Life 2, Red Faction (and 2), Far Cry, Soldier of Fortune, IGI2, ...). The only game I have had that absolutely needs a re-install is Halo. Far Cry needs a re-install. But, I have copied about 10 dll files that I restore after a reformat and it does not need a re-install.