3GS iPhone. Can't beat it in terms of browsing, productivity and ease of sync (im on mac if it makes a difference). I previously had a 1st gen jailbroken iPhone and wouldn't have updated if it had not gone all wonky (tried to update the OS to 2.1.14 to get apps, but lost all wifi and had other issues).
iPhone is great, but I admit not perfect. The biggest complaints I have is the hassle of switching between apps sometimes (for example getting an email notification of a new core77 forum post then clicking on it to go to safari), where it doesn't keep the same viewing mode (ie. i'm in landscape viewing in email, but when switching to safari it is set as portrait and vice versa). Overall though a very enjoyable experience. The amount of useful apps alone puts it far and above any other phone I've seen (though never seriously looked).
Previously I was on a samsung phone I got in HK about 3 years or more ago (pre-iPhone launch). Ultra series, can't recall the model though I have it around still somewhere...Super thin (so thin I actually broke it in half in my pocket), but for just calling and basic calendar stuff it was OK. I wouldn't expect much from such a thin phone (5.9mm thin - almost half the thickness of an iPhone), but if you don't need web/email it was OK. That being said I don't think I could ever go back to being fully "connected" like on an iPhone...
On a side note, I've never understood why cell companies don't do something like a free trial. I know so many people who thought they didn't need email, web, etc, only to finally give in an say "they could never live without it!". If the carriers could offer a free 30 day trial of a full smartphone I would doubt there would be many to go back to living offline and unconnected!