Scott Ritchie, an Ubuntu MOTU, has proposed that WINE be moved into Ubuntu's Main repository thereby making it shipping with Ubuntu by default in some form. This proposal is coming after he and several Ubuntu developers had discussed this idea last week at the Ubuntu Developer Summit...
One also has to add that there are also GPL open source software released under Windows that have not yet a direct equivalent in Linux (nor have they been ported, even though the code is available), and that there's still some specialised applications that doesn't run natively in Linux (and in those cases even RMS agree it's ok to use them, so let's hope some won't feel haughtyier than the epitome of free software advocacy ).
However, for Scott to succeed Wine will have to allow executing a Windows program when the user isn't the owner of the wine directory (sharing a group isn't enough atm, and 777 permissions either).
An also obvious mistake would be installing everything in the same wine directory. Let's hope he uses WINEPREFIX (or bottles?) because when you have to add DLL and tweak the registry, it can get ugly for other programs.