I've carried an iPhone for quite a few years. The iPod touch sucked me into the ecosystem and once I made the jump to the iPhone 3GS I've stuck with it as my smartphone of choice.
But having owned an iPhone for this long, I'm acutely aware of the fact that it is far from perfect, and that there are some severe limitations that come with the device. But the great thing about owning an iPhone is that you can tap into a vast ecosystem of third-party accessories to help you overcome most of these limitations.
All of these accessories have been extensively field-tested and have survived months of hard, and sometimes daily, use. This is the only way I know to be able to make sure that you'll be getting a solid product.
Here are some of the tools and accessories I use to help me get the most from my iPhone. If you have a favorite accessory or tool, feel free to mention it in the comments section below. I'm always on the lookout for new gear to try out!