I'm preparing myself for a return of the 60s - I don't see Republican majorities again for, at the very least, 8 years and probably more like 16 or 20.
2008 and 2010 will go a long way towards determining that. The GOP needs to gain governorships and state legislatures in the next two election cycles. If not, the Democrats will pretty much control the 2011 redistricting process. That will allow them to replace Republican gerrymanders with Democratic ones. If you think being a 30-seat minority party on a map the Republicans drew themselves is bad, just imagine how many more losses there will be on a map drawn by the Democrats.