I have had both the iPhone 3G, and the Galaxy S. I would choose the galaxy any day over the iPhone, for many reasons. Here are some.
Apps
Anyone can make an app for android, and google even have an easy to use online tool for it, what do Apple have?
Apple have a restricting app store that only approved apps can get into. Then, they charge the developer a percentage to sell their app!
Music
Android lets you get your music anywhere and be able to play it, use it as a ring tone, or send it to your mates (I'm Australian) with blue-tooth. It also have apps to download music, for free. (So I have heard)
Apple, you have to buy separate ring tones and no sharing! Unless you delete everything from that iPhone and sync it with another computer. Android let you use it with as many computers as you please, and you can even use it for media storage.
Conclusion
Apple and Android both have the pros and cons, but for me. Its Android all the way. You can always jailbreak your iPhone and make it work like it should. It will void your warranty though.
What do you think? Apple or Android?