Microlight flight bag contains freezer-suit, helmet (in bag) headset (in bag), GPS, gloves, knee-board, neck-warmer, tie-downs, some spare batteries for GPS, penlight torch, combination screwdriver and still has room for more. It's a Caribee 15-litre model in basic black, available at most outdoors stores. Make sure your flight-bag has decent zip-fasteners! Minimise velcro, the loop section of it wears out in 12-18 months.
Separate flight case (ATPL style, usually kept hidden in car) has charts, 2 X Icom A-20 radios, calculator, nav instruments, logbook etc. Does not go on flights, just used to hold stuff needed before flight.