Western front battles of World War II

Air Battle over Holland: Information about the Dutch struggle against the Luftwaffe during Fall Gelb
Battle of the Bulge: Website about the Wacht am Rhein, with information on both the battle itself and the battlefield today
France 1940: Website in both English and French about the Allied side of the German attack on France, Belgium and The Netherlands in 1940, with some excellent information not frequently seen in English
H O W I T Z E R . D K: Excellent reference guide, with photographs of several battlefields of Western Europe, as well as many AFVs. Also includes an extensive model gallery
La Bataille de Normandie: Information about the Allied landings on D-Day. Mainly in French, but with some information in English
Marketgarden.com - The digital monument: Information about the persons and units which fought during Market Garden
Military History Online - WWII: Several articles about the battles and campaigns of World War II. Also includes articles on other wars
Military maps of WWII: Very good resource for maps of World War II
OnWar.com - Military History Research: Tanks of all major nations of World War II, maps of the battlefronts and a timeline of World War II, as well as several articles. Also includes information on modern-day AFVs and military history in general.
The Maroon Beret: Interesting information about the Allied side of Market Garden
The Normandy Campaign 1944: Niklas Zetterling's exellent website about the combat in Normandy in 1944, with a lot of information about the German Order Of Battle
World War II Armed Forces - Orders of Battle and Organizations: Dr. Leo Niehorster's excellent website, with orders of battles for pretty much every country which fought in the war. His website also include errata pages for his books, and other interesting pieces of information
World War II day by day: Extremely detailed timeline of Germany during World War II, as well as many excellent articles, including a very large database of German vehicle markings
worldwar-2.net: Elaborate timeline of World War II, as well as many other interresting articles
WWII in Europe: Information and statistics about the European theater of operations