D-Day was the biggest seaborne invasion and the greatest military campaign the world has seen. From 6th June to 11th June (D + 5), 326,547 troops, 54,186 vehicles and 104,428 tons of supplies had been landed on the beaches.According to the D-Day museum in Portsmouth, the number of military personnel were:-

Allied troops landed in Normandy 156,115
American (Omaha & Utah beaches + airborne) 73,000
British (Gold & Sword beaches + airborne) 61,715
Canadian (Juno Beach) 21,400
Airborne troops (included in figures above) 23,400
Aircraft supporting the landings 11,590
Sorties flown by allied aircraft 14,674
Aircraft lost 127
Naval vessels in Operation Neptune 6939
Naval combat ships 1213
Landing ships and landing craft 4126
Ancillary craft 736
Merchant vessels 864
Personnel in Operation Neptune 195,700
American 52,889
British 112,824
Other allied 4988

According to the D-Day museum website the following casualties were suffered:-

Casualties on the British beaches were roughly 1,000 on Gold Beach and the same number on Sword Beach. The remainder of the British losses were amongst the airborne troops: some 600 were killed or wounded, and 600 more were missing; 100 glider pilots also became casualties. The losses of 3rd Canadian Division at Juno Beach have been given as 340 killed, 574 wounded and 47 taken prisoner.

The breakdown of US casualties was 1,465 dead, 3,184 wounded, 1,928 missing and 26 captured. Of the total US figure, 2,499 casualties were from the US airborne troops (238 of them being deaths). The casualties at Utah Beach were relatively light: 197, including 60 missing. However, the US 1st and 29th Divisions together suffered around 2,000 casualties at Omaha Beach.

The total German casualties on D-Day are not known, but are estimated as being between 4,000 and 9,000 men.

Naval losses for June 1944 included 24 warships and 35 merchantmen or auxiliaries sunk, and a further 120 vessels damaged.

Over 425,000 Allied and German troops were killed, wounded or went missing during the Battle of Normandy.  So much so that during a holiday there hubby did not want to go swimming in the rivers there.)

Sources: 
http://www.britishlegion.org.uk/remembrance/d-day/history-of-d-day/facts-and-figures-of-d-day

http://www.ddaymuseum.co.uk/d-day/d-day-and-the-battle-of-normandy-your-questions-answered#casualities