Yep, that seems to be it. I should first do a search on trac before spamming here! 

But my first reaction when something basic as this goes wrong is blame myself and ask for help :-)

On Sat, Aug 22, 2009 at 11:40 PM, Judah Jacobson <judah.jacobson@gmail.com> wrote:
On Sat, Aug 22, 2009 at 2:37 PM, Peter Verswyvelen<bugfact@gmail.com> wrote:
> Okay, I'll file a bug report. Maybe someone else on Windows could confirm
> this behavior?
> On Sat, Aug 22, 2009 at 11:36 PM, Jason Dagit <dagit@codersbase.com> wrote:
>>
>> On Sat, Aug 22, 2009 at 2:14 PM, Peter Verswyvelen<bugfact@gmail.com>
>> wrote:
>> > The following program
>> > http://hpaste.org/fastcgi/hpaste.fcgi/view?id=8445#a8445
>> > should echo the ASCII code of each character the user types, on the fly,
>> > with no line buffering whatsoever.
>> > But it doesn't. At least not under Windows's cmd, and even less with
>> > msys.

This is probably the following issue:

http://hackage.haskell.org/trac/ghc/ticket/2189

-Judah