I observed that nvcc does not warn when using uninitialzed variables in my kernel.
The Visual Studio 2008 compiler gave me this warning, when I changed my kernel to run with OpenMP (very easy to do, since CUDA is more restrictive than OpenMP) .
Compiler warnings are very useful and improve the software quality, so I hope that such warnings will be added to the nvcc compiler. Better error messages would be also very useful.
Something else: There are no bugs reported on the registered developers page … it would be nice to know of bugs in the CUDA toolkit to circumvent them until a bugfix is out.