"MacBook Pro Software Update 1.4
This update includes fixes that improve graphics stability, address issues with external display support and 3D performance, and improve Thunderbolt device support.
After update OS build version = 10J4138
(corrected, originally doc listed 10J4035)

System Requirements: OS X 10.6.7"

BTW - The 2011 MacBook Pro owner that previously reported problems with an Apple (single link) DVI adapter and Apple DVI displays wrote this update solved that problem. (I assume he also applied the EFI update.)
Unfortunately he'd already bought the $99 Apple Dual-Link DVI adapter last month, which he reported worked. (His original report on the problem (w/screenhot) was in the Mar 31st, 2011 archives.)
  

"MacBook Pro EFI Update 2.1
This update includes fixes that resolve an issue with Turbo Mode in Boot Camp, and improve performance and stability for graphics and Thunderbolt.

Boot ROM or SMC Version Information: After updating users Boot ROM will be MBP81.0047.B0E

System Requirements: OS X 10.6.7"

I wondered if this would enable SATA III on the optical bus as some later build 2011 MBPs have mentioned but the first reply I saw in apple's forums said it didn't on his 2011 MBP 15in. Later mails said the same thing. (The other SATA issue reported previously is with 2011 17in MBP's and SATA III drives - OWC had created a SATA Cable Shielding Kit as a workaround for that.)
(FYI - on Friday a reader with 2011 MBP said this update caused major problems with his Checkpoint Disk Encryption software.)
  

"iMac EFI Update 1.6
This update includes fixes that improve performance and stability for Thunderbolt.

After the update Boot ROM version = IM121.0047.B0A

System Requirements:
Requires the Mac OS X 10.6.7 Update for iMac (early 2011) be installed"

FYI - Despite not being listed by Apple in the docs, OWC said in a blog post that after the 2011 iMac updates, SATA III (6Gbit) was enabled on the new models. (Optical drive bus still 3Gbit.) Previously, testing with their SATA 6G SSDs showed only SATA II/3Gbit link speeds.
  

Mac OS X v10.6.7 Supplemental Update for iMac (Early 2011)
The Mac OS X 10.6.7 Update for iMac is recommended for all early 2011 iMac models. It includes general operating system fixes for Mac OS X Snow Leopard that enhance the stability, compatibility, performance, and security of your Mac, including fixes that:

• Improve the reliability of Back to My Mac
• Resolve an issue when transferring files to certain SMB servers
• Address various minor Mac App Store bugs
• Address minor FaceTime performance issues
• Address issues with graphics stability and 3D performance
• Improve external display compatibility
• Improve Thunderbolt device support

FYI - the title above was later changed - now Apple just calls it "Mac OS X 10.6.7 Update for iMac (early 2011) 1.0" - but still lists 10.6.7 as required (as of 5/6/2011).
  

"iOS 4.3.3 Software Update
This update contains changes to the iOS crowd-sourced location database cache including:

• Reduces the size of the cache
• No longer backs the cache up to iTunes
• Deletes the cache entirely when Location Services is turned off

Products compatible with this software update:

• iPhone 4 (GSM model)
• iPhone 3GS
• iPad 2
• iPad
• iPod touch (4th generation)
• iPod touch (3rd generation)

This update is available via iTunes."

Here's the page on iOS 4.2.8 Software Update for the CDMA model iPhone 4 that lists the same changes.
  

• Review of iMac 27-inch (3.1GHz, Spring 2011) (cnet)
• New 27-inch Core I5 IMac/3.1GHz Speed Results (pcworld)
• (2011) iMac Intel 21.5" EMC 2428 Teardown (ifixit)

• How to combine multiple audio interfaces by creating an aggregate device on Mac OS X v10.6 Snow Leopard
• iMac Fast Start: The new user's guide to iMac
• Mac OS X Server v10.6: How to enable SSL certificates for Push Notification Server
• iMac (Mid 2011): Memory specifications
• About the SD and SDXC card slot
• iTunes: Advanced iTunes Store troubleshooting
• iBooks: Frequently Asked Questions (FAQ)
• How to tell if your Intel-based Mac has a 32-bit or 64-bit processor
• Compatibility of Apple wired headset models with iPhone, iPad, and iPod models
• iPod Displays a Red "X" Icon
• Where are my iTunes files located?
• About Apple Magic Trackpad and 27-inch LED Cinema Display Update for Windows
• Locating iPhone wireless carriers

• Why Do Intel's 3-D Transistors Matter? (informationweek)
• Demystifying SSD Wear Leveling (informationweek)
• Duke Nukem Escapes From Development Hell (forbes)