With coming over from the UK, we have the oppotunity to buy our tickets before we leave.
We normally buy a 21 day Ultimate ticket which basically allows you unlimited access to all the parks, water parks, Pleasure Island & Disney Quest for 21 days from the first day of use!
I am so happy that they offer Annual Passes for those who are very lucky enough to come to WDW more than once a year, and to make it better, the DVC renewal rate makes it an even better deal.
On our first trip we purchased our tickets at Downtown Disney when we arrived which took forever. The next trip we got them through the Disney Store and I believe we got the tickets there but that was 2 years ago so I may be wrong.
I just purchased my tickets at the Disney Store. The price is exactly the same as buying on Disney.com except that you don't have to pay for shipping and you've got the tickets in hand. No matter what state you live in you pay the Florida tax because the tickets are to be used in Florida.
I have searched other on-line sites. I never found any that had better prices. I am also always leery of buying from 3rd party dealers.