I have created a 2008 Roster / Depth Chart based on the current 2007 one. Names in red are free agents, names in blue are restricted free agents and would need to be tendered an offer, and guys in black are already signed for 2008. The blank yellow boxes are the "holes" that need to be filled, preferably in free agency (I prefer to use the draft for depth and for competition to the guys already on the roster... let them win the job and the whole team is better for it).
http://www.thenetrat.com/2008%20Depth%20Chart.xls ( a link to which can be found at http://www.thenetrat.com )
DE being the number one need. Backup DT (to rotate in) being important as well. MLB and SSLB and RCB all should be found in free agency, the current roster doesn't contain anyone I would wish to start in 2008 at those positions.
I truly hope that Woody gets re-signed to play RT. He is better at it with no training camp and little practice then anyone the Lions have had playing there in at least a decade, longer actually.