What will iOS5 features will not be supported on a 3GS?

Question

Everytime a new iOS comes out, the feature set that is supported on the iPhone 3GS gets watered down and watered down.  Yeah yeah yeah, I know I need to update my hardware, but it just isn't in the budget this month.
Other than some of the more obvious things, like Siri and mirroring, what features in iOS5 will not be supported on the iPhone 3GS hardware?  I thought someone would put out a list, but there is nothing in the wild yet.

Answer 1

A better response: http://support.apple.com/kb/HT4959
Learn which iOS 5 features your iPhone supports:
iOS 5 Feature
iPhone 3GS
iPhone 4
iPhone 4S
Notification Center
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iMessage
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Newsstand
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Reminders1
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Twitter
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Photo editing
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Wireless setup and activation
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iCloud
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Wi-Fi sync
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FaceTime2
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VGA/HDMI out3
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HDR (High Dynamic Range) photos
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Siri
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AirPlay Mirroring
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Notes:
Location-based reminders available on iPhone 4 or later
FaceTime requires a Wi-Fi connection. FaceTime may not be available in all countries or regions.
Requires the Dock Connector to VGA Adapter or Apple Digital AV Adapter, sold separately. Video Mirroring only available on iPhone 4S.
For a list of additional features and capabilities available on all iPhone models, see the iOS 5 Software Update page.
Message was edited by: CWulf
Message was edited by: CWulf