You guys are sadly mistaken! WiFi location services work OK for you now because you are all testing it in a place where you have an internet connection. Namely, the WiFi network in your home or business (or publicly available WiFi). But when you travel up a street, VERY FEW WiFi hotspots are freely open for internet access. YES... WiFi location services (like Skyhook Wireless) might know where those WiFi hotspots are located, but you need access to the internet to get that data!
Once you move away from a WiFi hotspot that allows you access (internet connection), your WiFi-only iPad will be hopelessly inaccurate with regard to location. Me, I want location services to work ANY time I need them, not just when I have access through a WiFi hotspot.
And it's NOT just navigation (turn by turn) apps that need a GPS. One of my all time favorite iPhone apps is Geocaching. Hunt for "treasure" all over the world. And much of that "treasure" is hidden in areas far from WiFi hotspots. Without a GPS in the iPad you can forget about using Geocaching.
As more and more nifty apps come along to take advantage of location services, more and more WiFi-only iPad owners are going to be wishing they had gotten the 3G model instead.
Mark