EZ, I don't see how the staff can afford NOT to take 2 DE's and 2 DT's, and maybe 3 at one or the other position. Looking at the Roster it appears that 6 players at each position to fill 2 spots is ideal, see below.
-2009 Season
DE (6 Players)
Harvey, David / Sr.
Turner, Barry / Sr.
Allen, Pierre / Jr.
Meredith, Cameron / RFr.
Williams, Josh / RFr.
Ankrah, Jason / Fr.
DT (6 Players)
Suh, Ndamukong / Sr.
Crick, Jared / So.
Moore, Terrence / So.
Steinkuhler, Baker / RFr.
Randle, Thaddeus / Fr.
Pensick, Cole / Fr.
Next Year I think the Rosters at DE and DT may look like this, I don't count Cotton because I am not convinced he won't end up on the O-Line:
-2010 Season
DE (7 Players)
Allen, Pierre / Sr.
Meredith, Cameron / RSo.
Williams, Josh / RSo.
Ankrah, Jason / RFr.
Walker Ashburn / Fr.
Tobi Okuyemi / Fr.
Donovan Vestal / Fr.
DT (7 Players)
Crick, Jared / Jr..
Moore, Terrence / Jr.
Steinkuhler, Baker / RSo.
Randle, Thaddeus / RFr.
Pensick, Cole / RFr.
Jay Guy / Fr.
Chase Rome / Fr.
For 2011 the Rosters at DE and DT may look like this, I am guessing Crick goes pro (This doesn't include any 2011 recruits:
-2011 Season
DE (6 Players)
Meredith, Cameron / RJr.
Williams, Josh / RJr.
Ankrah, Jason / RSo.
Walker Ashburn / RFr.
Tobi Okuyemi / RFr.
Donovan Vestal / RFr.
DT (6 Players)
Moore, Terrence / Sr.
Steinkuhler, Baker / RJr.
Randle, Thaddeus / RSo.
Pensick, Cole / RSo.
Jay Guy / RFr.
Chase Rome / RFr.
2011 looks to have 6 players per position, not including any incoming recruits. However since recruiting fills needs 2-3 years down the line, the most important years to look at for 2011 recruiting focus is the 2013 chart. Below lists what players on the current roster will be available in 2012 and 2013, this assumes ZERO attrition via injury and/or departures which I think we all know is unrealistic.
-2012 Season
DE (6 Players)
Meredith, Cameron / RSr.
Williams, Josh / RSr.
Ankrah, Jason / RJr.
Walker Ashburn / RSo.
Tobi Okuyemi / RSo.
Donovan Vestal / RSo.
DT (5 Players)
Steinkuhler, Baker / RSr.
Randle, Thaddeus / RJr.
Pensick, Cole / RJr.
Jay Guy / RSo.
Chase Rome / RSo.
-2013 Season
DE (4 Players)
Ankrah, Jason / RSr.
Walker Ashburn / RJr.
Tobi Okuyemi / RJr.
Donovan Vestal / RJr.
DT (4 Players)
Randle, Thaddeus / RSr.
Pensick, Cole / RSr.
Jay Guy / RJr.
Chase Rome / RJr.
The 2013 list shows only 4 players per position, and this doesn't even account for any attrition. Considering that the 2011 class is to fill the needs in 2013-2015, I think the staff takes 4-5 players on the D-Line in 2011.