VGR - 40 (1-27 gives you + 19-44 HP; 28-49 gives you + 3-19 HP; 50-99 gives you + 1-3 HP)

• You receive only 100 extra HP between 51-99 Vigor, so it is very unwise to level Vigor past 50.

END - 40 (stamina gain will stop here entirely except for resistance)

• You recieve only 10 extra Stamina between 41-99 Endurance, so it is very unwise to level Endurance past 40.

VIT - No soft cap (as equip load will continue to increase by 1 per point)

• Vitality also increases Poison Resistance by 3 per point of Vitality between a score of 30-40.

ATT - 40 (Max slot is 10 and final slot only unlock at 99 Attunement)

• 0 Attunement Slots below 10 Attunement.
  
• 10 gives you 1 Slot
  
• 14 gives you 2 Slots
  
• 18 gives you 3 Slots
  
• 24 gives you 4 Slots
  
• 30 gives you 5 Slots
  
• 40 gives you 6 Slots
  
• 50 gives you 7 Slots
  
• 60 gives you 8 Slots
  
• 80 gives you 9 Slots
  
• 99 gives you 10 Slots

STR - 40/60 (60 is secondary soft cap where 1-2 AR increased per point.)

• While two-handing, your strength is multiplied by 1.5, allowing you to reach the soft cap at 27, the hard cap at 66)
  
• Due to Diminishing returns, it is common for some strength builds to stop at 60 Str.
  
• Two-handing does not improve your defenses. However, it will decrease stamina drain when blocking.

DEX - 40/60 (60 is secondary soft cap where 1-2 AR increased per point.)

• Also reduces spellcasting time and damage from falling.
  
• The casting speed cap is at 50 DEX.

INT - 30/60 (30 soft cap for pyromancy and dark spells / 60 for pure sorcery.)

• 50 INT is enough to cast every Sorcery in the game.

FTH - 30/60 (30 soft cap for pyromancy and dark spells / 60 for pure miracle.)

• 45 FTH is enough to cast every Miracle in the game.

LCK - No soft cap (as item discovery will continue to increase by 1 per point)

• Characters begin with 100 Item Discovery. For each point of luck you receive one point of Item Discovery, up to a hard cap at 99 Luck (199 Item Discovery).
  
• Man-Grub's Staff's, Anri's Sword and Hollow infused weapons damage scales with LCK.
  
• Luck also increase auxiliary effect value on weapon (Bleed/Poison/Frost)

More info+stats in the future.
All information is taken from Dark Souls WIKI.
Please report any inconsistencies and questions in the comments.