Currently Being ModeratedOct 26, 2013 6:44 AM (in response to Jay Tovah)
Thank you for your question. Unlike applications purchased from the Mac App store, Mac OS X will show "Download" even after it has downloaded. This is beneficial if you need to install Mac OS X onto an alternate drive.
If you have installed OS X Mavericks, you will still get the software updates even though you see the word "Download" by it in the Mac App Store. As long as you see Version 10.9 in About this Mac, you are currently up to date:
From the Apple menu, choose About This Mac. The About This Mac window shows your OS X version number.
Thank you for using Apple Support Communities.