BeQuiet Dark Power 650W is worth buying... very quiet and stable, and more importantly very efficient too.
OCZ are decent enough - just put one in my i7 rig and cant fault it.
yes it is
• Ultra-high efficiency @ *** almost 87%. *** <-- nice
• Very stable voltages with no "over-volting".
• One of the most silent units
• Excellent modular cable system.
• Good Package and accessories