New Base Class Library in .NET Framwork 3.5

System.TimeZoneInfo
System.DateTimeOffset
System.Collections.Generic.HashSet
System.IO.Pipes (Named Pipes)
New Suite-B encryption algorithms
EventSchemaTraceListener
Support for new Vista event log (ETW)
System.Threading.ReaderWriterLockSlim

Just hope there will be new lib in 4.0 :)

from http://jack-fx.com/tech-article/108.htm