I was using older hardware so I didn't face that transition until after it was over for most people.
My last new motherboard for many years was a super socket 7. After that I wasn't real interested in buying the newest stuff, but I was buying and selling a lot of used parts on eBay so my PC changed frequently. My final AGP setup was an nForce2, Mobile Barton CPU and a Radeon 9800 Pro. That was a great system.
I was happy with it until youtube switched to H.264 and I couldn't play their videos anymore. I was so behind the curve that a web site abandoned me.
When I finally bought a new motherboard it was an AM3 Phenom2. I was only playing Morrowind so I didn't need a video card upgrade, but I was faced with the switch to Express. Besides budget, I also worried about the reliability of high powered gaming cards. I was used to having backup hardware around, but with PCI-Express I had nothing.
So I decided to buy a cheap card to start, with a bigger card to be bought someday in the future whenever I actually needed it. My reasoning was that low end cards are usually reliable, so it would make a good fallback if my future "big" card turned up dead one random day.
I loved my 9800 Pro, so I wanted to stay with ATI. So I bought a cheap Radeon HD4350 as my "starter" card. By chaining together some benchmark tests (hard to find for low end cards), I decided it was faster than the 9800 Pro so that was good enough for me. I figured after I bought an HD5750/5770 or whatever, the 4350 would be my fallback that wouldn't require different drivers.
I ended up getting irritated with the 4350. It had some flickering surfaces in games, and there was some problem with dual monitors (don't remember the specifics on that one). It didn't live up to my good experience with the 9800 Pro. So when I did buy a "serious" card, I bought an NVidia GTX260, not a Radeon. Thus my "fallback" 4350 card ended up being an inconvenient oddball. It's the only ATI/AMD Express graphics card I have, still.
I never got engaged with early PCI Express cards. My exposure to those generations was as late AGP models instead.