I was hoping the new version of the IDE 1.0.2 would include a fix for the extreme lag some are experiencing. The fix has been developed and is well documented by eried. It involves using an alternative rxtxSerial.dll file he created. See http://arduino.cc/forum/index.php/topic,46977.0.html for more info.
I included the fix in http://arduino.cc/forum/index.php/topic,118440.0.html XD