For iPhone, iPod Touch, and iPad
Source
It all sounds a bit "meh" to me
4.x Support for the iPad
iOS 4.0 features for iPad (Multitasking, Folders, etc.)
Updated Carrier Signal Strength Display (3G iPad only)
Increase in the length of the smaller signal bars
The method in which signal strength is calculated has been enhanced
Fixes glitch that can let a user get into the phone app while the phone is locked via “Emergency Call” by dialing a random number and quickly pressing the lock button after dialing that call
Fixes the alarm bug cause by daylight saving time which affected Australian iPhone and iPod Touch owners
iPad screen rotation lock switch is converted into a sound/silent switch in iOS 4.2 (Just like on the iPhones)
AirPrint Wireless Printing with Print Center
Import .ics calendar files directly for events
Birthdays icon has been changed in calendar
Updated Carrier Settings (US is AT&T 9.0) (iPad 3G only)
Text search on web pages
2 new fonts for Notes in Settings (Helvetica and Chalkboard)
New icon for Voice Memos (iPhone and iPod touch only)
Updated applications
AirPlay (replacement of AirTunes, AirPlay will offer stream video, music, and photos over WiFI
More than 30 new keyboards and dictionaries, including Arabic, Greek, and Hebrew for iPad
New Text Tone Alerts (New & Original tone lists) (iPhone only)
Ringer & Alerts on/off switch (Settings > Sounds) for volume buttons (iPhone only)
Assign different text tone alerts to each contact (iPhone only)
YouTube voting
New Multitasking Animation
New Parental Controls for deleting Apps, changing mail accounts and location services
FaceTime shortcut from Messages app
New wallpapers in Settings
New Bookmarks design (iPad only)
Minor improvements in UI graphics
Restores full Field Test Mode
I’m excited for the new features to drop as it makes it’s way closer to perfection.
iOS 4.0 features for iPad (Multitasking, Folders, etc.)
Updated Carrier Signal Strength Display (3G iPad only)
Increase in the length of the smaller signal bars
The method in which signal strength is calculated has been enhanced
Fixes glitch that can let a user get into the phone app while the phone is locked via “Emergency Call” by dialing a random number and quickly pressing the lock button after dialing that call
Fixes the alarm bug cause by daylight saving time which affected Australian iPhone and iPod Touch owners
iPad screen rotation lock switch is converted into a sound/silent switch in iOS 4.2 (Just like on the iPhones)
AirPrint Wireless Printing with Print Center
Import .ics calendar files directly for events
Birthdays icon has been changed in calendar
Updated Carrier Settings (US is AT&T 9.0) (iPad 3G only)
Text search on web pages
2 new fonts for Notes in Settings (Helvetica and Chalkboard)
New icon for Voice Memos (iPhone and iPod touch only)
Updated applications
AirPlay (replacement of AirTunes, AirPlay will offer stream video, music, and photos over WiFI
More than 30 new keyboards and dictionaries, including Arabic, Greek, and Hebrew for iPad
New Text Tone Alerts (New & Original tone lists) (iPhone only)
Ringer & Alerts on/off switch (Settings > Sounds) for volume buttons (iPhone only)
Assign different text tone alerts to each contact (iPhone only)
YouTube voting
New Multitasking Animation
New Parental Controls for deleting Apps, changing mail accounts and location services
FaceTime shortcut from Messages app
New wallpapers in Settings
New Bookmarks design (iPad only)
Minor improvements in UI graphics
Restores full Field Test Mode
I’m excited for the new features to drop as it makes it’s way closer to perfection.
Source
It all sounds a bit "meh" to me