If taking your stuff by plane is primary reason for getting the bag, I would first suggest checking out the baggage rules of the airlines you are likely to fly with.
My experience with kitegear is on KLM, TAP, Malaysian and Arke. All have different baggage rules and I have found myself packing things in various different combinations depending on the airline to escape or reduce baggage charges.
Some of the things to keep in mind are:
1. Airlines rate sports equipment differently. Sometimes golf bags are free outside baggage allowance. Sometimes free if they fit under your normal allowance. Sometimes a flat fee, which can be different for different types of sports equipment. Hence, sometimes the kite 'golf' bag idea can get you around this. Sometimes kite stuff is actually not taken (see British Airways from a few months ago, although I think this has now changed again).
2. Airline uses piece system (mainly in USA - 2 pieces up to xx pounds each) or Weight system (Europe - total kg limit). If total overall baggage weight, this is normally 20kg, but Arke has a comfort class where you get 25kg and I get 30kg on KLM with FF card).
3. Individual Bag Length. If it goes on the baggage conveyor, never a problem, but most kite bags are 140 or 150 cm long which do not fit, so they then want to know what is in there. For surfgear, Arke has cut off at 165cm, so if under this length and fits under your kg limit, then not a problem. Otherwise you need to work out if cheaper to pay extra kilo charge or pay a flat fee for sports equipment. Factor here is do you have a wave board or just twin tips.
4. Bag Weight: In any case, all european airlines will not let you take any one bag being over 32kg. I have a Dakine Airwagon which I can recommend due to good build and big wheels, but when it had 3 kites, 2 boards, 2 bars, harnesses, wetsuits, pumps ect, it gets over 32kg, so have to put stuff eslewhere anyway. But one 32 kg bag on TAP was OK and only had to pay 50 euro return (they lost it both ways however...) On KLM, a single surf bag over 20kg gets very expensive. Hence on KLM, not good to take the airwagon.
5. Destination. Different rates to inside europe and outside europe. Again this varies between airlines.
6. Travel Partners. whether you go alone, with 2 or in a group can also change how and where you pack things and ....this varies between airlines.
7. Get Creative. Other ideas are to remove the fins and pads from your boards, tape them together, wrap in bubble wrap and pack them in cardboard. In which case they could be considered as 'art'. Good if 'art' travels for free. Kites and bars then go in a big hold all tote bag which fits on the baggage conveyor (less chance of being lost...hiring a board for a day or 2 is a better option than hiring everything). Also you can try having a nice conversation with a sales or marketing manager from the airline in advance and getting an exemption....again depends on the airline. Also begging and negotiation at check-in can work as well. Although this seems to be less effective nowdays.
Anyway, just some things to think about before shelling out 150 euro for a travel bag. Especially if you are going to travel often and on different airlines. In which case you may find youself becoming more of an excess baggage geek than myself. Unlikely, but you never know...
Enjoy your travels.