It took a few minutes, but I managed to find four different threads about this question in October and November alone (for example here) and some more just before that. My search was hardly exhaustive. Perhaps it is high time this was made clearer in the sticky.

The correct answer is 27A/B and 27 J/K, where you get unlimited legroom. It also feels very spacious and doesn't feel like the "third cabin" - you have an uninterrupted view ahead of you.

The only excuse for taking another seat is if you desperately prefer leather to cloth (in which case take any seat forward of this row) or it is a very high priority to be quickly off the plane. Also, I suppose if you manage to nab D or F of whatever turns out to be the front row of ET, this will have a CE configuration and hence be wider - but this is tricky to do, and for most people legroom is more of a priority.