The Galaxy S phone (The first edition, GT-i9000) is an excellent phone made by Samsung. It runs Android Froyo 2.2 (with 2.3 soon to come), but it looks just like an iPhone, but it is way better, with more features and more customization possible.
It has a 4" super AMOLED screen, which is really bright with really good colors. It has a 1GHz single-core CPU and 512MB RAM. The performance of it is really great (Although in Android 2.1 there was some issues with lag that could be fixed with a third party lag fix, but the overall performance has improved in later versions of Android.) and it can run pretty much everything and every game in the market.
Bundled features is quite nice, the TouchWiz launcher is actually all right, but if you wish you can always replace it with some other launcher, like Launcher Pro.
The battery usage can be a little problem for me. It usually holds for the day (3 hours of music, fetching new tweets and facebook messages every 5 minutes, syncing mail, 1 - 2 hours of surfing) and I usually charge the phone every night, but I guess it can be a problem for some. There are some solutions though, like that extra battery case Samsung is selling, some custom ROMs got battery fixes. I've also noticed that if you turn of data usage you can save a lot of battery, having the phone holding for almost a week (although obviously you can't sync mail or using the Internet that way).
Another issue, not too big for me, is the GPS system. It isn't very accurate (although it has become a bit better in later versions). If standing still and walking is all you do, it will perfome just fine (tho it can take about a minute for it to completely locate you). But, if you reach higher speeds, like on a bike or in a car, and take sharp turns, it will continue forward for a couple of seconds until it notices that you made a turn, and then correct after that. So I will not recommend this phone if you will depend on it to navigate in yuor car on the road.
If you get this phone, I strongly suggest you get involved with it more technically and flash a custom ROM. I would suggest MIUI. It adds a lot of nice features and it has a really nice look, and is pretty fast too.