Have had the Galaxy S since 19th June and have fully exploited the potential of this device now, loaded it with multimedia and installed more than 20 very useful apps. The phone is nothing less than phenomenal and does not have any setbacks (i.e iPhone's ridiculous signal problem) and handles everything that i have had to throw at it so far, 720p video captures, DIVX/XVID movies, high res pictures, live audio streams, full internet browsing, 3G video calling and it does it all with minimum fuss and the screen (Super AMOLED) is simply the best bar none. Yes the iPhone has higher resolution but pixel for pixel it has better contrast and colours, the vividness of the screen will spoil you and you will never want a normal TFT again.
The SWYPE text input works very well, the whole experience has just been so smooth and painless.
Some negative points however... Battery life is terrible if you play with it all the time, but this is not an exclusive problem to this phone.
No Flash support as yet, but Froyo release will remedy this.
Overall from social networking to multimedia handling, this phone does it with a smile and never breaks a sweat.
If you can afford it, buy it.