The Google G1 can be very intuitive at times but there are other features that just bugs me. (ie. the information bar doesn't always pull down when need to, lack of on screen keyboard, no file manager or video player by default. etc.). The biggest gripe I have is how hard it is to find GPS on/off switch. For me, it was completely non-intuitive. Instead of keeping it in Settings/Wireless Controls, they have a dedicated menu under Settings/Security & Location.
Searching the web wasn't very helpful for me so hopefully this post can help anyone looking for GPS switch. PS - by default, GPS is deactived, so My Location feature is based on IP/Cell Tower proxmity.