The way I see it, Chevy has two possible routes to go: they can hold down the traditional camp, or they can join the competition and forge ahead with their vision of the future. Chevy trucks in the past, including the current Chevy Silverado, tended to go the traditional route. The 2009 Chevy Silverado, with its stacked square headlights and wide, flat grille, looks like the Chevy pickups of the '90s, the '80s, and the '70s (maybe even the '60s, too). If you took the bow-ties and labels off the 2009 Chevy Silverado and took it back in time to show it to pickup truck owners in 1972, I'm pretty certain they'd be able to identify it. (I think the 2009 Dodge Ram would be identified too, actually.)
So will the next generation truck, the 2012 Chevrolet Silverado, follow that trend? I think so. Possibly some interesting front end and hood heights and contours will surface, as with the 2009 Toyota Tundra. And possibly the stacked headlights will live on, but with a more modern bezel, or overall shape. The wide grille will probably stay too, but perhaps change in height. Will the interesting fender flares from the 2007-2009 Chevy Silverado stay? They're pretty distinctive, so perhaps they'll stick as an added identifier. Perhaps the tailgate will become more interesting, with distinctive taillight clusters. I don't really know. After all, pickup truck buyers are a very traditional bunch.
I don't really think Chevy will go overboard with a major departure, or try to leap too far into the future (that scary place). Ancillary models like the Chevy Avalanche, and compact trucks like the Chevy Colorado, are the appropriate place for design bravado. These trucks are less grounded in (or stuck in?) tradition and can showcase the design talents in Detroit. The Chevy Silverado probably will not feature a sloping grille, or car-like headlight clusters, or anything too radical. But maybe they'll surprise us.
It's a risky business, messing with tradition. If you change the truck too much, you'll anger the loyalists; if you don't change enough, you'll lose the guys who want the best truck, or the younger guys who haven't found their brand yet. I just hope Chevy gets it right.