Everyone will have their own opinions but here is my 2 cents:
Best
1)Tom Brady QB Michigan (2000 draft - 199 overall)
No explaination needed on this one.
2) Richard Seymour DT Georgia (2001 draft - 6 overall)
Seymour played in five Pro Bowls, has been named to four All-Pro teams, and has been a member of four Super Bowl Patriots teams (3 time winner).
3) Matt Light T Purdue (2001 draft - 48 overall)
Light is a 3× Super Bowl champion, 2× Pro Bowl selection and one time All-Pro selection.
4) Asante Samuel DB Central Florida (2003 draft - 120 overall)
2× Super Bowl champion, 2× Pro Bowl selection and one All-Pro selection. Started career in NE slow (6 picks in first 3 yrs) but exploded in 2006 (10 ints) and 2007 (6 ints). Would be 3 on my list if he was still a Pat.
5) Vince Wilfork DT Miami (FL) (2004 draft - 21 overall)
Immovable rock in the center of the Pats D-line. He has 1 Super Bowl champion, 1 Pro Bowl selection and 1 Second-team All-Pro selection
Honarbale mention:
David Givens WR Notre Dame (2002 draft - 244 overall)
Deion Branch WR Louisville (2002 draft - 65 overall)
Ty Warren DT Texas A&M (2003 draft - 13 overall)
Dan Koppen C Boston College (2003 draft - 164 overall)
Logan Mankins G Fresno State (2005 draft - 32 overall)
Matt Cassel QB USC (2005 draft - 230 overall)
Worst
1) Chad Jackson WR Florida (2006 draft - 34 overall)
Pats moved up to draft Jackson early in the second round. Proved to be too injury prone and immature for the NFL. Pats cut him before the start of the 2008 season. Patriot career totals: 13 rec -152 yards - 3 Tds
2) Bethel Johnson WR Texas A&M (2003 draft - 45 overall)
Like Jackson this speedy WR never developed for a 2nd round pick. While he had some nice Kick Off Returns he was awful as a WR. In his 3 years in NE he averaged 10 rec - 150 yards - 1.33 TDs. This with TB throwing him the ball. To add insult to injury. the next WR taken in the draft was Anquan Boldin.
3) Marquise Hill DE Louisiana State (2004 draft - 63 overall)
Hill tragically died in May of 2007 so it was possible he was going to develop but during his 3 years with the Pats he played in 13 out of a possible 48 games and totaled 3 tackles. 1 tackle a year for a second round pick? Brutal! Very next pick - Pro Bowl DL Darnell Dockett
4) Kevin O'Connell QB San Diego State (2008 draft - 94 overall)
3rd round pick lasted 1 season in NE before being cut. Total waste of a pick. When you consider how bad the Pats need a 3rd WR right now it has to hurt knowing WR Mario Manningham was draft by the NYG with the next pick in the draft
5) Dave Thomas TE Texas (2006 draft - 86 overall)
BB loves to draft TEs (Graham, Watson, Mills etc) but none of them have ever been great. Thomas only lasted 3 years in NE totaling 21 rec - 261 yards - 1 TD)
Dishonorable mention
Laurence Maroney RB Minnesota (2006 draft - 21 overall)
Adrian Klemm T Hawaii (2000 draft - 46 overall)
Guss Scott DB Florida (2004 draft - 95 overall)
Garrett Mills TE Tulsa (2006 draft - 106 overall)