Well: Update your system AND your signature now! ... There was a time when I simply put 10.4.x instead of 10.4.6 or 10.4.7 I believe. If rumours come true, we'll see 10.6.6 in very early 2011 (for the Mac App Store), so I wouldn't wait too long with updating your sig.
Mac user since 1987. Running Mac OS X 10.8 Mountain Lion on a MacBook Air 11" & an iMac 27" and whatever's newest for my iPhone 4s, iPad 3 and AppleTV 2.
Apple Certified System Administrator 10.6, Apple Sales Professional 2008-2011, Apple Certified Mac Technician.