Solaris 10 05/09 was has been released, which probably is the last release from an independent Sun.
Noteworthy changes are:
SSH with PKCS#11 support which means use hardware acceleration for SSH on UltraSPARC T2 and Sun Crypto Accelerator 6000.
Improved power management for Intel CPU (T-State, Power aware dispatcher and deep C-state)
Enhanced observability for intel CPU ( performance counters, Nahalem turbo mode)
Major iSCSI improvements and bug fixes.
IPSec improvements (SMF service, stronger algorithms)
Support for backing out patches with update on attach for zones.
Additional network drivers (NetXen 10, hyper GigE, Intel ICHI 10 and Hartwell)
And lots of bug fixes...
The complete document: Solaris 10 5/09 What's New
CPU and PCH Temperature Sensors in illumos
4 days ago