2 months before the release of the iPhone 4 I got mine from ebay, unlocked, brand spanking new 16GB 3GS for just over £300. Ebay is the best place (if you're careful and know what's geniune and what's not). I wouldn't bother with contract, I say just look around ebay. At the moment the price difference between the 3gs and the 4, the 4 is too expensive and the 3gs is too cheap for what it is XD. Makes no sense to me, but if you can find a good price on the 4, get the 4. If not get a 3GS, i'm happy with mine

And yes, i'm no fanboy I infact hate apple fanboys, I dislike MAC's too (overpriced and glorified) but I feel the iPhone is the best phone out there with the app store, itunes, apps, everything really. My only real complaint is the lack of ability to share stuff over bluetooth, but considering it's like an ipod too, you wouldn't really ask anybody for a song XD