I generally agree, but note that the 7E7 will have range roughly equal to the 777-200ER and 747-400 - Boeing wants the three to be interchangeable on a given route.
On the high end of the spectrum, a 747 Advanced may replace the 747-400 beginning around 2010, if the 744 can hang on that long. There is a gap between the 777-300ER and the A380 that needs filling, but it's not big enough for a totally new airplane.
The 777 will be around for a long time, and future derivatives incorporating 7E7 technology are not out of the question. A 777 super-stretch is a second alternative to close the gap above the 744, but Boeing would rather see the 747 remain in production.
Boeing will probably begin pondering a 737/757 replacement to fit in below the 7E7 around 2010, perhaps with EIS by 2020. If the 717 doesn't land a significant chunk of the Star Alliance order, it will be gone in a few years.
Unless Boeing's current super-jumbo forecast is proved stunningly incorrect, I don't see them producing anything larger than a modest 747 stretch in the near future, including a BWB. In their opinion, the very limited market does not justify the expenditure.
A new SST is very unlikely in the near term, although I do expect subsonic cruise speeds to creep slightly upward (the 737NG, 747X proposal, 777, and 7E7 are all a few Mach points faster than their predecessors). If technology advances permit, a 300-pax transpacific Mach 2+ SST might be feasible in 20-30 years, but I doubt private firms will take the risk of developing one without substantial government help. Hypersonic airliners remain little more than wishful thinking.
[Edited 2003-12-04 03:30:49]
Keynes is dead and we are living in his long run.