Posted this in one of the threads that got locked, re-posted it here as it looks like some may find it useful:
Don't ask why as I'm not sure myself, but I haven't missed an England game at Wembley since it was rebuilt, and as a result I've sat pretty much everywhere. For me the best place to go is the back half of the lower, best view and decent for atmosphere (on the extremely rare occasion there is any at England games).
The upper tier is quite high up, even from the front row you're still higher than you'd think. The atmosphere there is pretty dreadful by all accounts. The acoustics of the stadium aren't great, and I don't think noise travels up there or is contained very well (Club Wembley separating the two tiers of supporters doesn't do it any favours either).
Most regular England supporters I know try to go for the front 5 rows of the lower, as they are cheaper than the rest of the lower tier, the view isn't too bad and you still feel a part of the atmosphere.
I wouldn't fret too much about whether you're along the pitch, in the corner or behind the goal, as the view from everywhere in the ground is good as long as you're not too high.
For reference for people, there are 44 rows in the lower tier. I'm not sure how many there are in the upper as it varies depending where you are, but I wouldn't recommend being further back than around row 10. The seats up there are cheaper for a reason. I don't mean to worry people intending to buy the cheapest tickets, but just be aware that the view and most probably the atmosphere will be better elsewhere.