Blitzkrieg Commander 2 has quickly become our preferred set of WW2 rules for operational level scenarios. BKC 2 revolves around its command system, which while simple in concept, is very effective for this level of combat. The rules cover close assaults, scheduled bombardments, engineering, and more in an organized fashion that makes the system easy to grasp and highly suitable for group play. There are extensive army lists that cover the period from the Spanish Civil War to the end of WW2 with stats for every vehicle, artillery piece, or type of infantry that served in the war. Very similar to the Warmaster system, so if you've played that you can transition quickly to BKC 2.1/285th & 28mm WW2
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Skirmish & Operational Level Combat
Most wargamers have played some type of WW2 ground combat and it's no different with our group. Many of us in the group grew up with Tractics, scenarios from Wargamer's Digest, and railroad mats with masking tape for roads for our WW2 games! Today our group does WW2 in two separate scales; 1/285th for large scale actions and 28mm for skirmish. At this time we have British, Russian, and German forces for 1944-45 in 1/285th with more units for other theaters being worked on along with a wide array of terrain in this scale. For skirmish actions we currently have Russians and Germans for the start of Operation Barbarossa on the Easter Front in 1941, plus several units for U.S. vs. Germany in 1944-45. 
We use 1/48th vehicles instead of the more common 1/56th as we like the look of the large models with 28mm figures. While Blitzkrieg Commander 2 and IABSM 3 are our preferred rules at the moment, we're always ready and willing to try out new things for this period. Future plans include a "bathtub" Market Garden campaign in 1/285th, and greatly expanding our 28mm collections to do some large scale combined arms operations. Of course with the expansion of forces we'll also need to increase our selection of terrain, so that is yet another project to add to the list. WW2 continues to be a very popular period with our group and although you would think we would get tired of it after some close to 35+ years of wargaming, in reality we continue to push on and try to do more!
Over the years we've tried a large number of WW2 skirmish rules, ranging from Arc of Fire to Disposable Heroes, but our current set of rules for WW2 skirmish actions is I Ain't Been Shot Mum 3rd Edition. This set of rules features a card driven activation system (which can be customized) and combat where hits are expressed in numbers of kills and shock points. Leaders, or "Big Men" as they are called, are the focus of the game, enabling units to move, improve their firepower, and reducing shock to units. This results in a fast moving, chaotic game that is great for group play while allowing for large numbers of figures as well as vehicles on the board.