Another recommendation for Otter Valley Railway for a very positive customer experience and good pricing. The one hiccup with OVR is that they don't do through-the-website credit card payment. You can place an order and note pay-by-phone and they will call you to process your credit card over the phone. If you have a credit card tied to your PayPal account, they will process that online.
I have also ordered online from Credit Valley Railway and had a good experience, too. I have been in to the George's Trains store and was very happy with the selection. I recently purchased from them online and it was shipped the next day. Both of these stores will process credit cards directly online.
I attended a couple of train shows this fall and was generally pleased with the N scale offerings. Woodstock had a pretty great selection (maybe half a dozen dedicated N scale tables, plus maybe a dozen or so offering N mixed with HO). A lot of the selection is older, but I was pleased to find some recent Atlas and Athern rolling stock in mint condition that set me back about half of the retail pricing.