Be sure to pack the drive the same way it was shipped to you. If you really want to be careful, put the drive box inside a larger box and surround with packing peanuts.
Be sure to keep a backup at your shop until your client receives the drive and confirms the data is good.
As for drive recommendations, we use G-Techs. I have used LaCies with no problems, but stopped after hearing too many horror stories.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.4 QT7.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870
ATTO ExpressSAS R380 RAID Adapter, PDE Enclosure with 8-drive 6TB RAID
24″ TV-Logic Monitor
Final Cut Studio 2 (up to date)
Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN