For the reasons given above (real strength depends on optimization, not on the class you choose to optimize), there's also the lesser known Test of Spite Tier System:
Originally Posted by Olo Demonsbane
Here's the ToS Tier System as I remember it:
Tier -2: Pun Pun
Tier -1: An unbeatable build.
Tier 0: An effectively unbeatable build, though it can actually be beaten by the higher Tiers.
Tier .5: A build that can probably only be beaten if you have specifically prepared for it. Example: Sofawall's Cube build.
Tier 1: A build that has many effective tricks, insanely high defenses, and can end most encounters in a round. Example: A very effectively played Batman wizard.
Tier 2: Multiple great tricks and great defenses. Where I usually build for. Example: A CoDzilla or a Warmarked.
Tier 3: A build that either has one great trick or a lot of moderately good ones, while still having stellar defenses. Example: A well made Warblade, a good tripper, or a buff focused Sorcerer.
Tier 4: A build that, while still having a trick or two, has fallen very short on the defensive side of the line or has great defenses without being able to defeat an opponent on its own very easily. Example: A Charging Fighter or a VoP Monkadin.
Tier 5: A build that, while attempting to be optimized, still has neither good defenses nor a worthwile trick. Example: A typical fighter.
Tier 6: A build that *twitch* chooses feats for flavor reasons *twitch*