Ha when I opened the thread I thought it was going to be about hardware
changes over the years, but I suppose software/configuration is just as well.
Your history in that regard is much more illustrious than mine, lol. I guess that's why I was expecting a hardware thread. In my case...
I guess you could say my first "HTPC" was using a P4-based Acer XC Cube and WMC (XP MCE) as a PVR device for recording and playing SDTV. That went on a while (and I think I even still have some of the TV shows recorded to this day in dvr-ms or whatever the file format was) but it was only really ever used as a TV tuner and PVR and not much as a typical HTPC otherwise. Though it was connected to a TV it was also connected to a monitor at the same time (bedroom setup) and I think in all honesty I probably used the PC monitor more than the TV anyway, lol. Not much of an "HTPC".
Oddly enough from the advent and popularisation of HDTV, I actually stopped
using MCE (and any front-end at all) altogether. I think the main reason I stopped using MCE was because in Vista there was no longer support for ATi's TV tuner built into AIW products (which is what I was using). That and also because it always had that problem with replacing your file-tag-embedded cover art in music files with low-res equivalents! This despite the fact it would read and display the high res versions up until some random point where it would replace them with ones it downloaded itself
It was an incredible pain to stop this from happening and once it was still happening in Vista and I couldn't use the TV features, I just ditched it. I'm not sure if they ever fixed this in 7 but I never used it enough to find out.
From there, because of the state of digital cable (and sat) [HD]TV in Canada, it made using a PC for a PVR next to impossible as we don't have cablecard here. So, since then I just have a cable-company-rental PVR box for that. No more TV/cable interaction with a PC
My first true HTPC was built with/for my first HDTV and was a C2D-based machine (paid $270 for an E6600--the most expensive CPU I've ever bought and ever will buy, lol!). It's main use? Just a PC connected to a "really big monitor"--for web browsing and video gaming. There wasn't much media stuff going on TBH. Within a year of that I added a BD drive and started using PDVD for BD (and HD-DVD) playback, something I still do today albeit with the latest PDVD and having gone back and forth from PDVD and TMT over the years.
Video files I don't have many but those are handled with MPC-HC... Music OTOH that was always a main use. I went through various players after MCE and it's moronic file tag behaviour--foobar, musikcube/songbird, a few others, and eventually MediaMonkey, which I still use today.
Shortly after that first HTPC build I discovered the usefulness of a NAS box. At first it was a fairly low-end D-Link unit. Slow and crappy but did the job for the most part. Once I finally tired of the terrible speed of the thing, I eventually transitioned to a Qnap TS-219P II, which is what I still use today.
No server for me, I just don't have that much stored in terms of amount of data. No front ends either, heh. And not many HTPC setup lessons learned I suppose, as a result. My hardware changes over the years have been much more plentiful and eventful though.