The Bills are in a fairly decent spot right now. They can stay @ 11 and most likely get a good corner, linebacker, or lineman. Or, they can try to move up to get an impact player like Ellis or Dorsey if they're still there. Or, they could move down if their target is a wideout and still get more picks. I can see arguments being made for any of those moves, actually.
This team isn't one player away from a title, but another piece to the puzzle, especially one that could have major impact, certainly cannot hurt. For that reason, I could see moving up.
The Bills are lacking @ defensive back and linebacker and could use more help on either the offensive (interior or outside....I'm still not 100% sold on Walker as a RT) or defensive (still need a pass rush) lines. W/ that being the case, I could see standing pat and drafting in those areas.
Of course, everyone 'round here has gone WR crazy, and w/ good reason, as the Bills' red zone production has been atrocious and a big wideout w/ good hands and the ability to fight off tight coverage will help big time. So, if they can address this properly while adding picks that could add size to the LB and DB units, that would be a sound move also.