#2 Verify that Hardware is from the Same Manufacturer
One reason why the Wi-Fi Alliance certifies wireless networking products is to ensure that manufacturers develop equipment that works together.
However, some features are proprietary and must be used with compatible gear to work. Additionally, there seem to be more interoperability issues with the wireless N gear.
One contributing factor might be that the official standard isn't complete; vendors are releasing Draft products. The point: You should use the same manufacturer for all your networking gear to prevent potential problems.
If you haven't already chosen a brand to stick with, think about any special wireless equipment you might have or want. For example, if you want to stream photos, videos, and music from your computers to your TV using a wireless media extender, you'd want to compare these devices between the different brands. Therefore you could get an idea of what brand would be the best for you.
When nailing down a company to go with, you should also search for product reviews online. Just typing the model number into Google might bring up some reviews.
Compare two or three reviews to get an idea of what other people like or dislike about the router's features, user-friendliness, and performance.