None.
I own 2 wet suits, a dry suit, 3 regulators, 3 pairs fins, bc/w, lead, lights, camaras, and all other gear, mostly good stuff, and backup stuff i bought earlier before i knew...
but no tanks. tanks pretty expensive to buy and cheap to rent ($120 tank rents for $5 a day). They are heavy and a pain to fly with. They must always be serviced (filled) after use. The deterioate in storage (the hydro and VIP dates are always comming or gone). some dive boats i use prefeer or require you use their tanks.
They are available everywhere. they have a nationaly recognized inspection plan and are not complex. So i beg/borrow/trade or if all else fails RENT use of tanks. Might change if i started to do heliox or doubles...