Recently Solaris 10 10/09 (aka: Update 8) released. You can see the complete What’s New in the Solaris 10 10/09 Release doc for details, but here is a brief overview. You can download the release from sun.com/solaris.

• Two-Terabyte Disk Support for Installing and Booting the Solaris OS
• pcitool Utility
• nss_ldap shadowAccount Support
• Sun Validation Test Suite 7.0 Patch Set 6
• Turbo-Charging SVR4 Packaging (faster pkg installs)
• Zones Parallel Patching
• PVIO Drivers in Solaris 10 Guest Domains (I recommend snv_121 if you really need xVM)
• iSCSI Initiator SMF Service
• LSI 6180 Controller Support in Solaris MPxIO
• Callout Subsystem Scalability
• Driver for LSI MPT 2.0-Compliant SAS2.0 Controllers
• Broadcom NetXtreme II Gigabit Ethernet Driver
• Interrupt Remapping Support for Intel Vt-d
• SATA Tape Devices Supported by the AHCI Driver
• Sun StorageTek 6Gb/s SAS PCIe RAID HBA Driver
• Intel 82599 10Gb PCI Express Ethernet Controller
• Intel 82598 10Gb PCI Express Ethernet Controller
• NTP Version 4.2.5
• PostgreSQL 8.1.17, 8.2.13, and 8.3.7
• Samba 3.0.35

Additionally, a variety of ZFS improvements:

• ZFS and Flash installation support (Hybrid Pool)
• Setting ZFS user and group quotas
• Using ZFS ACL pass through inheritance for execute permission
• Using cache devices in your ZFS storage pool (Hybrid Pool)
• ZFS property enhancements; such as read-only properties usedbychildren/usedbydataset/usedbyrefreservation/usedbysnapshots and ability to bias primarycache/secondarycache
• ZFS log device recovery
• Using ZFS ACL Sets
• … and of course a bunch of bug fixes as well.