Like you, op, I started with a 5110. It was my mom's old phone, my parents gave it to me for a bit in high school freshman year so I could have my own phone to call them when I needed rides from tennis practice and other stuff. Still have it, actually, darn thing probably still works.
Got the Stripe for my birthday, which was definitely better, it had a camera, could do mms, could play (some) .jar games. Most of the ones I loaded onto it didn't run, but I had a few games. Also got the $5 WAP internet plan, so that was nice. I finally upgraded to an N900 after saving my money.
The N900 was the best phone created ever in the history of humanity. Keyboard, stylus, lens cover, kickstand, IR, FM transmitter/receiver, 32GB internal + microSD slot, free Palm OS emulator, Debian chroot, backlit keys, dual speakers, Carl Zeiss lens, Linux, hackable, actual multitasking, triple booting, Cortex A8 cpu, the list goes on. I could wax poetic about this thing for ages. Oh, and my $5 internet plan turned out to give me unlimited 3G, and the N900 actually had 10Mbps down rather than the common 7Mbps, which was excellent. Only real downside was the poor usb port connection (the only way to charge it), which eventually broke after a while, leading me to buy multiple batteries and an external battery charger, but eventually I started getting No SIM issues as well, and by then Android had a much larger software library and more powerful phones, so I decided to finally upgrade. Now, I use it occasionally to play music and do occasional tasks, but I can no longer use it as a phone without getting a regular SIM again, and there's still the battery issue, so I don't turn it on often. There was a mod to use the Palm Pre's wireless charging on it, I don't know if it's still possible to find one of those these days, I would like to try that one day.
I used my brother's Behold 2 for a bit between the N900 breaking and finally getting the battery charger. It ran Android, but this was before Android was anything decent, and I don't think it could even upgrade past 1.6 (even with custom roms). So I wanted to get rid of it asap.
Eventually I decided I needed to upgrade and put the N900 days behind me, so I picked up a MyTouch 4G Slide. It had a physical keyboard which I adored, the camera was really good, and it had a dual-core Snapdragon which was top-notch at the time so I wasn't going to worry about a slow phone. I liked the Sense UI that came with it, but I rooted it and put stock ICS on there as soon as I could anyway, which worked great. Sadly, it died less than a year after getting it, couldn't get it to turn on anymore, and HTC nor T-Mobile would fix it. And this one came with a contract, so I needed to outright buy a phone to replace it which would have been too expensive for me. Also, because it came on contract, we lost the $5 unlimited 3G deal, and had to get the $30 5GB smartphone data plan, which I wasn't happy about.
So that's when I went to the Nokia 3710, it was my dad's old phone. Used it for a while, it wasn't much better than the Stripe but at least I could install more software to it. There's not really much to say about that one.
Finally, I upgraded to a Nexus 4 (which I'm still using). Didn't have to mess with custom roms, updates directly from Google, quad-core cpu and 2GB of RAM, 720p screen, beautiful design. It's got a glass back, but I've dropped it so many times and neither the back nor the screen have shattered or even scratched. Still loving it, haven't felt the need to upgrade yet thanks to the specs (my main concern with phones) and KitKat, doesn't lag at all. I have been kind of itching for a Nexus 6, if the rumors are true, although at 4.7" the 4's screen is very slightly uncomfortable for my small hands. And even if it doesn't get updates past Android L, because of its popularity, I think it'll be community supported for years to come, so who knows when I'll need to upgrade it.