Given your scoring system, gotta go with:
1.) Marques Douglas (has moved from one 3-4 D to another 3-4 D...has averaged 67+ tackles and 5 sacks per season the past two years). Should top 160 pts in your league.
2.) Trevor Pryce (if he stays healthy, he should be a lock for 45+ tackles and 8+ sacks now that he's playing DE again). Should post 130 pts in your league with upside potential.
3.) Pat Williams (has averaged 66+ sacks per season since '00). Good chance at posting 130 pts in your league with little upside potential.
4.) Darnell Dockett (his 40 tackle/3.5 sack rookie campaign is simply a preview of coming attractions). I would be disappointed if he didn't top 120 pts in your league for '05.
Normally, DE's (as opposed to DT's) are the power scorers for IDP leagues. However...your league only awards 4 pts/sack, while allowing a handsome 2 pts/tackle. This tilts the favor heavily toward DT's and 3-4 DE's (Pryce is my only exception above).