Standby has problems, especially in Windoze 7. My GF has a brand new W7 PC (
not one I built, for a change
) and it was regularly crashing when Standby was used.
I can see why; the hardware state needs to be saved and restored and (as a hardware designer of many years) this is almost impossible to make 100% reliable especially on a legaly-compliant IBM PC compatible.
Hibernation is a lot more reliable because the hardware is actually powered off, and re-initialised when you restart. It also doesn't draw power.
Switching right off (Shutdown) is the best way however because everything gets cleaned-out, including memory leaks and all other garbage in the memory.
The only advantage of Hibernation is a slightly quicker startup, and possibly unusual situations like running the AFPEX flight plan filing app which fairly randomly forces a re-download of the 3GB Java app from NATS, which can be a right PITA if you are abroad on £10/MB 3G
Hibernating the laptop, with the app running, usually avoids the app download.