All of these graphs were done before Luclin. Thus they don't include FT beyond FT1, and they don't include focus items.
Wizard damage/second compared to rogue damage/sec, by number of seconds into the fight:
Well equipped (uber) wizard damage vs. poorly equipped (gimp) wizard damage. The X axis is seconds since the start of the fight, the Y axis is percent damage increase the uber wizard has over the gimp:
The above wizards have standard raid buffs, i.e. C2, etc., but don't have a bard.
This graph shows wizard damage with a bard, either singing cantana alone, or singing cantana and twisting in two pulses of chorus of clarity:
This graph shows bard usefulness in the above situation, as a percentage of wizard damage the bard is doing. Note that the damage shown is multiplied by the number of wizards in the group, which at max will be 4 (6 person group, -1 for cleric, -1 for bard). Note also that the X axis is in MINUTES of fight duration. Useful values are generally those before the 3 minute mark: