They haven't been updating as regularly as they used to but TestMatrix at http://www.exactmagic.com/products/testmatrix/index.html is a good tool. You can export reports to excel and with a few excel macros get some decent data extracted (though I admit the experience could be smoother).
I've not tried automating it in a build environment and if that's your goal you might want to see how that scenario plays out but it does work with both nUnit and MS Test (so if you ever find enough reason to move to TFS you are covered). Like the VSTS coverage tool it integrates with the Visual Studio IDE nicely highlighting code line by line. Better than VSTS it allows right click running of tests on the actual lines of code of the test itself; highlighting the region and showing a tooltip with a success report or exception details. Plus there's a time in method profiler stuck in there as well.
All in all a great IDE experience and worth a look - but again if build automation is an end goal you'll need to check that out.