Google Fodder: It's known that HTC (who make the Nexus One and Desire and many other Android-based phones) tend to put their antennae in the back of the phone and in the base.
But the back and base is where you tend to hold the phone, usually. In theory, I suppose, this keeps the antennae away from your head when talking, and more like down by your jaw or chin (depending on the head size).
The effect on reception appears to be negligible, unless you're already in an area with very marginal reception. Then it may make a difference.
CyanogenMod v5.0.6 for the Nexus One allows the screen/display content to rotate through 360 degrees....so you can hold the phone completely upside down with the base at the top...and happily use the screen. Yes, the buttons to touch are now at the top of the screen, but the phone isn't huge, so there is no real inconvenience in this.
I've just found that in a location where I get slow "G" throughput, by holding the phone upside down as described above, I was able to get "H"...and much faster throughput.
I'll have to play with it some more, but post this here in case anyone finds it useful.
For what it's worth, I've not seen any of the 3G reception issues with my Nexus One that have been reported in the US. The phone works perfectly for me.
35 minutes ago