I guess I am quite high up the list on spending on one trip as a percentage of miles accumilated:

United: 450K lifetime, 350K currently in account.

Hilton: 90K lifetime, 90K currently in account.

Starwood: 40K lifetime, 30K currently in account.

About to spend for my honeymoon:

United: 350K, 2 business tickets to SYD (would prefer to spend 240K for saver first but nothing available) plus 2 domestic coach tickets to wedding ceremony in Cape Cod.

Hilton: 66K, 3 nights hotels in Australia

Starwood: 30K, 3 nights hotels in Australia

Still got to pay for the other 2 weeks though, and this approach saves $17.5K on flights and $2K on hotels which leaves lots of money for good food and fine wine