The set piece, at least here in the U.S., is the 'Life's Book" for the 70 year old. It can be simple or especially well done and includes photos , stories from friends and relatives, newspaper articles and a career history (armed services as well, if applicable) and people form the past. Always appreciated and can be reviewed for years to come.
A simple but elegant Champagne Glass with "70" on it and tied with a silver ribbon (not black!). A "show" type poster set at the front door of whatever venue you happen to choose, fitted with silver ribbons and largish picture of the honoree.
Lastly, we attended a recent 70th, and the family put together 70 very small gift boxes (about 2 X 2 X 4 inches) and filled them with inexpensive, funny little gift items. He got a pair of silly cuff links that he thought he had lost decades previeously. Many of the guest requested and got a box or three, but the family is usually charged with putting them together. Alternately, 7 of the little boxes would suffice...