NuGet currently places packages in the solution folder. If you have many solutions in the repo that all use NuGet it leads to a lot of duplicate binary files in the repo. this slows down checkouts and can cause cluttering in the repo. Companies may also have existing policies for binary libraries in place.
If NuGet had the ability to configure the local path for packages these problems could be worked around. Such configuration could be placed in the exsisting packages.config file and perhaps in the global vssettings that are typically shared between team members anyway.
[global settings could then be copied to the local solution settings to make sure they are checked into version control]
Somewhat related to: http://nupack.codeplex.com/workitem/260
As that bug also discusses solution level settings, but different settings.
Note that this will not affect NuGet.Core but will be a feature of the VS integration.