Looking for a Sari in India? Here's the Real Deal.
With branches all over India, Nalli is one of the best sari shops you can get to. I've never seen a tourist in one of them. If you're a casual sari-wearer (and I'm not sure you can be because those things are hard to fold!) you'd be better off buying a tourist sari at somewhere like Dilli Haat.
Nalli's is for serious shoppers. The best endorsement I can give is that this is where my family always get ours.