Well, bad information or good information, BatteryInfoLite and BatteryDetective from Cydia say otherwise as in terms of total cycles and what the battery capacity was after a year of charging in some iphone 4's (mine and 3 of my friends, plus two iphone 3gs').
I suppose each person has different things
And this is also from Apple
Use iPhone Regularly
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down).
Charge Cycles
A
properly maintained iPhone battery is designed to retain up to 80% of its original capacity at 400 full charge and discharge cycles. You may choose to
replace your battery when it no longer holds sufficient charge to meet your needs.
Continually charging the battery when you don't need to, ie constantly keeping it topped-up is a bad idea with regard to battery longevity
And that's coming from Apple's official website.
And fyi, my iphone 4 battery after 316 full charge cycles was only down from 1420 to 1415 as opposed to my friends, whos batteries after roughly the same cycles were at 1160-1200 something
But I suppose its all subjective.