Another +1 for the Ogio bags. My bag is pretty much the equivalent of Dalai's system, but the handle and wheels are contained in the bag. Motocross gear bags are well suited to what we need. They can be large enough to take everything we need, they're often compartmentalised to separate various bits, and a lot of them come with handles and wheels to aid transport. If I spent more time at tracks where I had to carry my gear though, I'd invest in one of those little trolleys that have been posted about before and just carry everything including the bike in one go.