The original press announcement, which came out over the weekend, stated that Boeing was looking to update its 757/767 line, possiblty with a new airliner, in addition to the Sonic Cruiser, which has priority at the moment. Both projects, one of the projects, or none of the projects may go into serious final development. Its just too early too tell. Sales of the 767/757 have been slipping, partly due to the downturn in air traffic, and, sorry to say Boeing fans, the A332 is a hit for Airbus. (I am a Boeing fan too, so please no A vs B nonsense.)
The Sonic Cruiser, if built, may replace the 767ER on long range routes, but it is not suited for shorter-range higher density routes; for example, if DL were to purchase the Sonic Cruiser, we would not see it on ATL-MCO runs.
While the 767 and 757 are great planes, among the best out there, its time to update them, either by creating New Generation models (the 733 was a very good plane, but the 73G is even better) or start with something new (just like at a certain point the 72S was replaced with the 757). This is good news and progress, and how Boeing intends to stay competitive; it will jump start orders and in the spirit of competition, keep the pressure on Airbus.
Boeing mentioned new materials to save weight, lower fuel comsumption, possibily more range, new engines, new electronics, etc., etc. While the 767/757 have been updated over the years, bit by bit, further improvement is always welcomed by all, especially if the improvements will mean more comfort, less fuel burn, and save money.