My group are rather quirky in our choices, possibly due to being all the way out in (Wild) West Wales?
6mm micro-armour games are always popular whether WW2 or 'modern'.
War Machine and Hordes are big favourites.
DBA, HotT, Deadzone and Dreadball are popular for quick evening games.
Kings of War seems to be giving old Warhammer Fantasy armies a new lease of life.
Flames of War is popular, some play in 15mm and some play with 6mm micro-armour, some have both sizes.
Dystopian Wars naval is a recent addition as is Infinity.
19th century wars in 10mm are played by two of us.