Click to viewLeopard finally gets its second patch, and boy does it fix a lot of stuff. The first patch hit back in November, with test builds of the second making it out a month later. Here's a list of the major things the 10.5.2 patch fixes (including menubar transparency and Stacks).
• Airport connection reliability and stability (we've noticed some problems personally, and so have you)
• Back to my Mac for third-party routers
• Dashboard widget performance improvement
• Stacks fix! List view, Folder view, and updated background for Grid Vid View
• Menubar transparency disabling
• Less translucent menus
• Several iCal recurring meetings supports, bug fixes overall
• iChat Bugfixes
• iSync support added for Samsung D600E and D900i phones
• Finder bugfixes
• Mail bugfixes
• AFP network volume hanging fixed
• RAW support improved
• Preview bugfixes
• Time Machine bugfixes (some external drives not being recognized)
Plus lots of various other fixes (we tried to cover only the hot ones here). We'll have a full list shortly.
More info here [Apple]
There's also a Leopard Graphics Update 1.0 that comes after you install the 10.5.2 update, which according to Ars, it's just a set of updated graphics card drivers.