Driver and tools source code: 180 megs
Emulation and prototype files: 3 gigabytes
Documentation for microchip: 700 megs (PDF, Word, Postscript and other formats)
Discovering that the same person who wants the schedule not to fall behind has just decided to rename 4/6th of the components in the chip and wants all above files changed accordingly: Priceless
...my day has had other highlights (such as discovering an entire group of developers doesn't know how to use source control software and is checking files into Perforce randomly without checking that they actually work, and is telling other people not to synch to Perforce), but I think that sums up the best part fairly accurately.