I was totally stocked to get my Nexus One. When I got the N1 though, it did take some doing to get it working. Here are the issues I found and the solutions to the problems. Now you can find these solutions all over the net but I am just centralizing all the solutions please add any others you have found in the comments and I will update the post.
Wifi not getting passed the “Obasdtaining IP” msg and not connecting even though the login details are correct.
This seems to be a temporary issue associated with the specific session of the wireless network. The easiest solution is to reset the router.
No 3G or Edge signal at all(this does not mean flaky this means you never get any signal at all). This happened to me on O2.
Find your Carrier APN(Access Point Name) see O2 details below:
Name: mobile web
APN Type: default
What ever details you dont see above leave blank. The settings in the N1 is Settings>>Wireless & network>>Mobile networks>>Access point names>>menu>>add>>ENTER YOUR APN DETAILS (O2 IS ABOVE )
My 3G signal is poor. I have signal but its not very good.
Final solution from google fixes 3g signal bug and adds multitouch to all apps:
this will be an over the air update at some point.
Settings>>Wireless & Netowrk>> Mobile networks>>Network operators>>Tap Automatically
The bottom of the screen should you should see Registered. Job done you should see improvements immediately.
Dial *#*#4636#*#*>>Phone Information>>Change ‘WCDMA preferred’ to ‘WCDMA only’ at the bottom of the page. WCDMA is 3G so this setting forces it to only use 3G which means when there is no 3G signal u will get no net coverage. When u make the switch and get your strong 3G signal switch it back to ‘WCDMA preferred’ and you should find that your are still on good signal.
Hope that helps.