Most recent was the Blackjack, which was a fantastic phone. Once I learned a couple of battery saving tricks (keep it on edge for email, etc., only use 3G when browsing internet), it was the best phone I ever had. Small, light, and with the 3rd party apps...I could make it do anything.
Had the Q before that...Treo 650...iJam...treo 600...countless others.
Still...the iPhone has the most promise of any phone. still need 3rd party apps and some OS tweaks (landscape on demand in all apps, MMS, louder volume, etc.). But there is no competition for internet browsing, the phone part is easier to use than the competition, and the iPod has no peer. The PDA part just needs some improvement.