I'd expect the Montevina upgrade to occur this year, just to keep check of the Intel roadmap. However, it seems everyone expects a massive redesign; I doubt this - Montevina is just a speed bump, and any major form factor changes would be better served when the revised/smaller Westmere/Nehalem motherboards roll out in Q1/2 '09. And I'll bet it's Q2, not Q1, to allow 6 months product cycle from the Montevina update later this year, and to allow the desktop models to get some airtime first.
I know the rumor sites have been in full swing with this, but the design is wonderful and ageless - think Porsche 911 in its evolution through TIbook through now - why major change for change sake? OK, I see the maglatch as a 'tidy-up', but the trackpad is large enough already, really - anyone doing serious graphic work has a tablet, gamers have separate mice etc.
As for Montevina, well, wi-max has little immediate future in the UK due to bandwidth and population density; very few games will completely refuse to run on the 8600M GT's GPU [commercial suicide to release a game which doesn't run on 90% of 'average' gamers' PC's], the DVI port already allows HD viewing, albeit not 1080 'trueHD'; and finally, if DDR3 is the only option, as discussed it'll work out far more expensive to 'max-it-out', and DDR3's performance gains over DDR2 are slim.
A present MBP seems a very good way to see out the next 3-4 years, by which time the technology we speculate on will be mature and less expensive. Of course, by then, something else will be on the way, and we'll all be declaring Gesher/Sandy bridge to be 'old and clunky....'