Yes. Consider the "packages" directory to be equivalent to your "libs" directory that you mentioned in your question. This is the approach I personally take with my OSS projects.
We are investigating features that would allow MSBuild to auto download the needed packages, but that hasn't been implemented (as of NuGet 1.1).
I think some people may have already implemented such features on their own, but our plan is to look at having that feature built in to NuGet 1.2 or 1.3 hopefully.
I realize the reality was different when this question has been originally posted and answered, but fortunately the answer changed a bit. It is now possible to use NuGet to download dependencies via MSBuild using a Pre-Build event. You don't need to put the packages folder in your code repository, all dependencies will be downloaded and/or updated on build. It may a workaround, but it looks decent enough. See the following blog post for details: http://blog.davidebbo.com/2011/03/using-nuget-without-committing-packages.html
Since this question was asked there is now an easy workflow to use NuGet without commiting packages to source control
From your package manager console you need to install the 'NuGetPowerTools':
Install-Package NuGetPowerTools
Then to enable your projects to support pack restore you need to run another command:
Enable-PackageRestore
Now you are ready to commit your code base without the packages folder. The previous command changed your project files so that if packages are missing they get automatically downloaded and added.
AS of 09/20/13, there is something called "Nuget Restore". You actually don't have to check in package folder if you wish to do so. (Especially if you are using DVCS)
This post has become very outdated. The answer is still NO, but the solution has changed.
As of NuGet 2.7+ you can enable automatic package restore without including the NuGet.exe file in your source (this is undesirable to say the least) and if you use any modern DVCS you can ignore the packages folder. If you need any special customizations you can create a nuget.config file in the solution root.
Also, with the new csproj format you can avoid the extra nuget.config files as well since that is integrated now. Please check out this post which explains that better: