I think this year I will be a little more specific:
ACW:
Confederate Artillery -- the Washington Artillery of New Orleans
Union Infantry in sack coats and forage caps in firing line
Middle Ages:  
Bannockburn-- Robert the Bruce and Company
Agincourt -- Dismounted Henry V
American Revolution: 
Continental Artillery
WWII:
Normandy: Lord Lovat's Commandos relieving Pegasus Bridge
82d Airborne 6lb Airborne Antitank gun defending La Fiere causeway.  Airborne Jeep (I know licensing can be a pain, but there appear to be workarounds.)
Omaha Beach -- BG Norman Cota, Rangers 29th Division
Pacific:  Iwo Jima Marines (in M41 Field Jackets)
Vietnam:
Marines in Hue City.  Ontos. Mechanical Mule
Australians (the mixture of FALs and Sterlings would be cool)
Napoleonic:
Battle of New Orleans (well it IS Napoleonic by extension).  Marines (both RM and American) Artillery, pirates, Regulars, Local militia, Highlanders in trews, personality figures etc...
WWI:
1916- 1918!
Verdun, 2nd Marne, Meuse Argonne.   Poilu in Adrian Helmets, Legionnaires in Khaki, Hotchkiss Machineguns, Chauchats. French 75s. German 77s. Sturmtruppe with Kar-98s, MP-18s, Artillery lugers with snail drums, MG-05/15s and flame throwers .  Doughboys and Marines with 37mm trench guns, M1917 Enfields (Army only -- Marines only used Springfields) , BARs.  Plenty of Personality figures.