Max stats in FFX

Maximum stats for the Standard Sphere Grid (US and Japan versions):
max stats			lowest		spheres needed

9999 hp				320 (Rikku)			33
999 mp				10 (Wakka)			25
255 str				5 (Yuna, Lulu)		63
255 def				5 (Yuna)			63
255 mag				5 (Tidus, Auron)	63
255 magdef			5 (4 characters)	63
250 agl				5 (Auron, Lulu)		63
133 Luck			17 (3 characters)	29
122 Evasion			5 (4 characters)	30
0 Accuracy			~~~			~~~
-------------------------------------------------------------------
Maximum stats for the Standard Sphere Grid (International and PAL versions):

same, except:

230 Luck		54 spheres
60 Evasion		14 spheres
-------------------------------------------------------------------
Explanation:

Strength, Magic, Defense, Magic Defese: Obvious. 255 is the maximum, and every point helps.

Agility: The most important thing Agility does is reduce the amount of time between a character's turns. In this regard, Agility maxes out at 170. The other thing Agility does is increase the number of turns a character gets at the start of battle. In this regard, Agility maxes out at 250. (Add First Strike for an extra turn.)

Luck: To never miss, you need 75 more Luck than the target.
To never miss under Darkness status, you need 90 more Luck than the target. To always get a critical hit, you need 100 more Luck than the target. The enemy with the highest Luck in the North American and Japanese versions is Hornet, who has 33 Luck.

Evasion: In order to always evade an enemy attack, a character's Evasion and Luck must add up to equal the sum of the enemy attack's accuracy constant and the enemy's Luck. The attack with the highest accuracy constant and Luck in the North American and Japanese versions is Malboro Menace's Mega Gastric Juice, which has an accuracy constant of 240 backed by 15 Luck, for a sum of 255. If you have 133 Luck, then having 122 Evasion guarantees attacks will miss you if possible.

Accuracy: Max Luck guarantees criticals, which also guarantees hits, making Accuracy worthless.