If you are boat diving, space is limited, so a big bag might not be a good idea. I put my kit together before I get on then carry my fins, mask, gloves, hood, reel, smb etc in a mesh goody bag - mine is rectangular one and has two carry handles and a long zip on the top - I can't find a link but I got it at Puffin. It is something like
this and
this although mine is made of string mesh fabric. I also carry on a
dry bag.
For travelling, I have a large wheeled Scubapro bag, but to be honest I prefer the cheap canvas wheeled bag I picked up for £20 from a luggage store on a retail park. It doesn't shout 'Scuba gear - nick me!' I also take my mesh goody bag with me.
HTH
Helen xxx