I agree with the very deep pockets required for a dane (or any giant breed). Just for normal meds etc, you pay more as they require larger doses.
We've had 2 danes and a greyhound, and over 13 years spent over $50K at the vets. This was due to health issues, allergies, anxiety and few operations, and palliative care for cancer.
Even with that, we would not have not had the dogs in hindsight, as they were all awesome beings and brought us so much joy.
If you are prepared for the possible costs, great danes are well worth it, but make sure that you talk to many people to sort out the good breeders from the bad.
Greyhounds are awesome as well, although not a giant breed.
ETA: Our last dane lived to 11 years and 8 months with cancer for the last 6 months or so.