Ooh, look at everyone jumping on the League Two/Powell bandwagon!
Seriously though, he is a quality young player. My gut feeling was that he won't be a top, top player, but it is so hard to tell - he's clearly very good technically and has improved huge amounts since I first saw him play. I'd imagine he'll play for England if he does go to United/Arsenal/Chelsea irrespective of how well he develops, though!
My England team after the Euros would be:
---------------------Hart-------------------------
---Walker------Smalling---Cahill-----------Cole----
---------------Wilshere---Rodwell-----------------
--Chamberlain--------Rooney-------------Young---
------------------Welbeck------------------------
Hart picks himself. I feel Micah Richards is overrated. Still miles better than Glen Johnson, but not the messiah everyone seems to be making him out to be. Walker is better IMO and definitely has more potential. I don't rate Phil Jones, and I think Caulker is certainly a good shout for a future centre half to partner Smalling, as I don't think Cahill is England starting quality.
Cole at LB is likely to remain - he'll be good still in two years' time and is streets ahead of any other English LB right now. Gibbs is better than Bertrand if he stays fit, but both are slightly behind Baines (although he's another I feel is slightly overrated).
Wilshere has to start in the middle - he has the potential to be world class (along with Hart) and England only really have Cole and Rooney who are presently world class. Rodwell is probably the best partner in that deep position.
Chamberlain and Young are England's two future wingers - Walcott is not the same for England as Arsenal, and whilst he may presently be better than Chamberlain, he possesses less natural ability. Rooney has to start, and would be effective in the trequartista role he often drops into for United. He also has the connection with Welbeck and Young, which is a bonus.
Welbeck is the best striker (bar Rooney) and his pace and work rate make his inclusion pretty simple.