Hi All.. i'm new user of desire.
Been using it since last 4 days.. it is a whole new experience to me as previously i'm using iphone for almost 2 years....
Like it very much but the battery is really sucks... need to charge everyday....

I believe you need to charge iphone everyday as well~~  
Your battery will go better after 1 or 2 weeks use with proper charge...
better if you are on custom rom....
I'm on AOSP rom (oxygen) and quite happy with it...
No set cpu, no juice defender....
i get around 28 hours of battery life with
almost 2 hours of calls
few sms and whatsup
1 hour+ of ebook reading
3g on all the time, only off for 7 hours during sleeping,
facebook, tweeter, weather and maildroid sync every hour

I only charge my iphone once is 2/3 days depends on the usage...

downloading right now...!!!

Rovio has released Angry Birds Seasons, a free Christmas-themed level pack that also includes the missing Halloween levels, onto the Android Market. The iPhone version is set to follow.

The 25 new levels of the Season’s Greedings level pack will be unlocked at a rate of one per day in the lead up to Christmas. It’s a veritable advent calendar of pig-squishing delights. The first level suggests that presents have now taken the place of the Halloween edition’s pumpkins as the bonus items of choice.

Speaking of which, the aforementioned Halloween edition finally arrives on Android under the guise of the Trick or Treat level pack.  This batch of 45 levels brings a spooky theme to the Angry Birds universe, along with a notably stiffer challenge. So that’s 70 levels (plus bonus stages) of bird-pinging fun for free. Rovio really is getting into the spirit of the season.

The iPhone version of the Christmas levels should arrive as a free update to Angry Birds Halloween “within hours,” according to the developer’s Twitter account.

Well, then are you comparing same usage under your iphone and desire?
If yes, then maybe iphone battery are damn good~~
I never have iphone, so cant comment much~~