Apple iPhone 3GS

alright i have a quick ? for you IPHONE users....i currently use the DROID ERIS and have been thinking about comming over to the IPHONE.....the few things that are keeping me from moving to the iphone is that i would be downgradeing to a 3 megapixel camera from a 5 megapixel camer...this IS a BIG deal for me being that i travel A LOT...also id be looseing the android market and OS which i REALLY REALLY REALLY like....my girlfriend has the IPHONE and it is very customizeable however just not quite as much as my ERIS ...i would really like to go to the iphone because of the larger screen and because it comes with twice the memory which i need for my pics and stuff like that...pretty much i am to the point that im about to honestly take a quarter and flip it and go with which ever one it lands on ....ALSO another question i had is what is the difference between the iphone,iphone 3g,iphone 3g s?? BESIDES THE MEMORY AND CAMERA what is the difference between the 3??? if ANYONE has any advice to help me make my decision between the two it would be greatly appreciated THX!!!
IN A WORLD THAT DOESENT...DROID DOES!! .... ok ok ya ya besides talk on the phone and look at the internet at the same time