So there you have it...about as clar as mud
HTC are the Iphones main competor and the Desire now comes in many flavours. Desire, DesireHD, HD7(windows), Z etc etc.
I did seriously look at a IP4 but it was the cost of the contract that swayed me to the Desire which is a great phone. Browsing like all these phones depends on signal strength. When on wifi its great. Battery life as stated can be dire. There are widgets that allow you to power manage the phone, but its mainly the screen size that kills the phoens. Either a spare battery, or as someone said a cheap phone..
The GUI on the iphone looks great however, the Android OS is just as good and as easy to navigate and Capcake is due out soon (Android 3.0) which has more improvements.
The decision is yours, but find a decent shop and get them to let you play with both types of phone, as it will come down to personal preference.
Just remember that if you want the best browsing experiemce, then its going to be Android as they allow ALL contant to be shown and not restict what you look at like what apple do. Just remember your quote on FB the ohter day about freedom of the NET.