A new revolutionary version of Qalculate is ready; this time with arbitrary precision, fractions, matrices, RPN, function and data plotting, boolean operations, exact mode, exchange rates, a new math display widget, increased function flexibility, new functions, ... ... and bug fixes. You really ought to check this one out.
For the next version I promise I will try to concentrate on polishing and bux fixes, so hopefully next version will be the first beta. I do however really need your bug reports for this to happen.