Hardware wise, droid has the upper hand, larger screen, higher res, faster processor, longer battery charge.
What the iPhone has going for it is a sleeker construction and UI, more apps that are usually higher quality, a more precise/accurate/sensitive screen, better audio if that matters to you.
Both will cost the same per month once you get data, and seeing as they are smartphones, I strongly believe they should both have data plans.
I can't really compare cameras first hand. More megapixels don't equal better shots, better lenses do. I haven't taken any with my friend's droid, yet, so I can't comment on how clear the pics are, although I'll say that the iPhone's is really clear to me while I'm also okay with the lower resolutions.
The iPhone also has the plus of iTunes working with it, which is pretty nice for organizing music, although it feels slower for me.
I would not get either at the moment right now unless it is an absolute must though. In less than a month, Apple with have their keynote and be releasing the 4th generation iPhone. From leaked prototypes, it is supposed to have a higher res rear camera, a front camera for video chat, MUCH higher res screen. perhaps the same res as the iPad, and a smaller form factor. The screen is 0.3 inches smaller, supposedly. It keeps the glass front and it's possible for it to also have a glass back (NOT a screen, just a really hard cover). Battery still isn't user replaceable.
Oh hell, I'll just link the images.
http://gizmodo.com/5520164/this-is-apples-next-iphone
It's a pretty big change in design relative to the jump from first gen to second/third gen.
Also, the screen WON"T be AMOLED, so that's another pro for the droid.
http://www.intomobile.com/2010/05/26...nstraints.html
But yeah, wait until the announcement for the new iphone and official specs before making a decision, because you will be stuck with whichever phone for 2 years, and they are doubling the early termination fees for smartphones on AT&T. Verizon already raised it if I remember correctly.
P.S.
The 4.0 firmware will have multitasking if that makes a difference. If you can't wait, jailbreaking allows it too. Actually, jailbreaking and the extra functionality that comes along with it such as creating a hotspot out of your phone, tethering, ...free apps...., is a pretty huge plus for the iPhone.