I can update on that...
I have one client that insists on using NIS 2010, and it turns out, that it uses less resources than it used to. I bought a machine with a years subscription, on the same Norton product, and it tested out well enough - it replaces several stand alone programs I am using now; however, I really like stand alone programs, as I feel that full suites are just too complicated to run smoothly and efficiently.
ESET's products may be an exception to that, as they seem to totally separate their products within the suite. NOD32 is hard to beat, but I couldn't see the performance difference between it and Avast v. 5.