http, smtp and other networking protocols - yes. xml/sql is too large things. actually, haxml package is already included in GHC sources distribution and i think that it should be excluded from there because it's too large, far more than any other package bundled with GHC
The problem I'm having with SQL right now is that there are a number of not complete and splintered implementation efforts. Having one library outside GHCs libraries but still promoted as the default implementation (and hosted under haskell.org) would be enough. Same for XML. I think most of my problems would be solved if cabal-get turned out to something like Ruby Gems so I could easily pull the packages I need to the machines I need (and also get dependencies and a way to remove the packages without leaving files scattered on my file system).