Street Fighter Alpha 3

Here's the most recent tier list:

Top Tier:
Yun
Chun-Li
Makoto

Upper Tier:
Ken
Dudley
Yang
Akuma
Urien

Middle Tier:
Akuma
Urien
Ryu
Oro
Ibuki
Elena

Low Tier:
Necro
Alex
Remy
Q
Hugo
Twelve

Bottom Tier:
Sean

Ops, sorry, I thought you were talking about SF3:Third Strike...

Currently, there's no official tier list for SFA3, but V-Akuma, V-Zangief, V-Sakura, A-Dhalsim, V-Ryu and A-Guy are widely accepted as being the best characters in the game.

The most commonly accepted tier list seems to be:

S Class:
V Akuma
A, V Dhalsim
V Sodom
A Class:
V Sakura
V Claw
V Karin
B+ Class:
V Zangief
V Sagat
B Class:
V Rolento
V Ryu
V Charlie
V Cody
A Gen
C+ Class:
V Cammy
A Guy
A, V Chun-Li
V Ken
C Class:
A, V Adon
A, V Rose
A Dictator
A, V Blanka
V Juni
D Class:
A, V Dan
A Boxer
V Honda
E Class:
A, V R.Mika
A, V Birdie
V Juli

Got it from SRK. I disagree with little things here and there, but all in all it's a pretty accurate list. Missing SFA3U and console characters though.