Unfortunately, standby mode has never been 100% stable for me, regardless of hardware or operating systems - and this is a lot of different motherboards and CPUs (both AMD and Intel), and a wide range of operating systems (Win9x through 98SE, Win2000, XP, Vista, Win7). It works most of the time on Win7, but once a blue moon I'll get a BSOD in the nvidia drivers (my workstation), and my laptop simply won't start (entering a state where the power button turns off immediately, rather than the keep-pressed-x-seconds... I believe this is a chipset or BIOS rather than OS issue).
It's a real shame, because standby mode uses about the same power as power-off state... and boots a lot faster than hibernate.