Also be wary of the fact that the standard conditions used will also change depending upon what temperature unit you are using to view your case. When viewing in C or K the standard temperature used is 15C, when viewing temperature in F or R the standard temperature being used is 60F.
A guy I work with has developed (and continues to develop) iOS engineering applications. They can be found here: http://www.activeminds.ca/iphone.php
Darren
Another vote for Avast here - I used to use AVG, but it was somewhat slower to update for new viruses and false positives. And Avast talks to you - that's worth the admission price right there.
And there is also another HYSYS clone available as Petro0707 mentioned, KBC's Petro-SIM is also being developed, but with more of a refinery focus. KBC use it as their internal modelling tool for their consultants, but it can also be purchased from them. More information on it is available...