My very first digital camera was a Sony Mavica. Technically, it wasn't mine. It belonged to the company I worked for at the time. My general manager knew I was into photography, so he'd let me take it home on the weekends.
Almost everything I shot with that Mavica was a snapshot of a person. The shot above is of my girlfriend at the time--she was patient with me as I shot disk after disk of portraits.
Digital was also less expensive. At a time when I was making $10/hour, inexpensive photography was important. The Mavica stored images on 3.5" 1.44MB floppy disks. When the disk was full (about 10 photos,) all you had to do was pop out the disk, throw it in your computer and copy the images over. It was life-changing. The images were 1.6 megapixels, so they weren't great for printing. But they were great for emailing or putting on the web. Suddenly, I didn't have to wait to see what my photos looked like. I could experiment with different lighting, locations, and poses and get instant feedback. The quality wasn't even close to 35mm, of course, but I could experiment with the Mavica until I got the look I wanted, then shoot final frames on the 35mm.
I recently picked up a Mavica FD90 and a Mavica FD100 used. They are newer then the model we had at work, but they were close enough to get me to fork over the $8 asking price. I had to buy both, because the FD90 came with a charger, and the FD100 had dual memory slots (so I could use a Sony Memory Stick.) Though after playing with them for a bit, I realized they do, in fact, have a USB port. There's no practical use for them, as far as I can tell. It's just nostalgia. I took a few photos with them, and instantly recognized the look. Grainy, low-res images that are actually small by today's web standards.
I sort of accidentally started re-collecting the old cameras I've used over the years. It started with a Canon AE-1 I found on Craigslist and has progressed from there. I get sidetracked from time to time and buy an old camera that I haven't previously owned. At some point, I'd like to have a collection of every camera with which I've captured an image.
What was your first digital camera? Do you still have the first photo you took?