I'll take a stab at it...
QB: Kerry Collins, alcoholic (gut shot to Amazinz...

)
RB: OJ Simpson, killed his wife and her lover
RB: Jamal Lewis, moves blow for buddies
WR: Randy Moss, runs over traffic cops
WR: Michael Irvin, loves coke and whores
TE: Randy McMichael, beats hhis pregnant wife
K: Sebastian Janikowski, alcoholic (haha... and Kerry's new oakland drinking buddy)
DST*: Rod Smart, insane (c'mon... "he hate me"?)
DB: Brock Marion, coke head
DB: Patrick Bates, beat pregnant girlfriend 3 weeks before baby's birth, then kidnapped baby, then beat mother with a gun
DL: Leon Lett, hopped on something new each week
DL**: Ray Lewis, killed two people... or at least "obstructed evidence"
Honorable Mentions:
RB: Ricky Willaims, pothead
WR: Rae Carruth, murdered pregnant girlfriend (what IS it about pregnant women that pisses NFL players off so much?) so he wouldn't have to pay child support
TE: Mark Chmura, sexually assulted his children's babysitter
DL/LB: Leonard Little, DUI manslaughter
DL/LB: Cornelius Bennett, charged with rape, sodomy, sexual abuse, unlawful imprisionment
* I assume DST stands for special teamer? no idea... can't think of any bad boy special teamers anyway... crazy Rod has to do. If you saw any interviews he had in the XFL, you'd know why...
** Since there was no LB category, I added Ray Ray as a DL
That's about it, for now. I'll add to the list if I come across some more good ones.