Cancellara is near the top of my list because he raced with enormous heart and strength--frequently attacking for the win and never giving up. But, I can't quite give him full marks for today's race. He's guilty of having over-estimated himself, and in hindsight (which is, of course, always a tad unfair), his ride in E3 looks extravagant.
Today Cancellara never looked as good off the front as he did in E3. He never had the same other-worldly impetus on the downstroke of each pedal rev, and he didn't shut down the gap to Chavanel anywhere near as quickly as he would have last weekend.
I'll also point out that, so far, Cancellara's having almost exactly the same Classics season Boonen had last year (2nd in San Remo followed up with a very spirited ride to the podium in Flanders)--that's an extremely impressive feat in its own right, but not good enough to qualify as a success by the rider's own standards.
Nuyens, on the other hand, had to do everything right to win today. For starters, a number of posters have pointed out how strong and important teams like BMC were; but, posters have noted this almost as a slight to Nuyens, as if the strong teams did him a favor. So far, though, I haven't noticed other posters commenting on how hard it is for a rider with Nuyens' characteristics to win Flanders with a team like Saxo Bank this year.
At the very least, Quickstep, Sky, BMC, Leopard, Garmin, Katusha and Vacansoleil all have better rosters for this race. For Nuyens to get it right today, he had to be tactically astute, cool, very strong, and of course lucky, too. Still, a perfect ride for him, in my opinion. Add that to his earlier semi-classic win in Dwars Door Vlaanderen and his decisions to skip Omloop and K-B-K, and it looks like he's done everything right at every step leading up to and throughout Flanders.
I either give Chavanel a tie with Cancellara for second or a very close third. He was strong, smart, and gutsy. With a little more luck in the sprint, he could have done a little more, too... Either way, a big step forward for Chavanel and a necessary result for Quickstep on a day when Boonen wasn't quite brilliant.