This is actually a reply to both rubix_1011 and nemi_PC. You guys are assuming far too many things here.
We’ll start a generalization first (you seem to be in that mode), then we'll cover my situation next. First off, as the article noted, even in the highest end AGP cards, there is essentially no penalty for AGP. If the x1950Pro is enough card for you, it is foolish to go out and spend a bunch of money to upgrade to a PCIe system just for the sake of having a PCIe system. An AGP version of any particular card many be a bit more than the PCIe, but it’s not that bit of a hit in the whole scheme of things. Likewise, is is also probably foolish to "upgrade" from AGP to PCIe and stay at skt 939, since eventually you'll have to replace all that stuff, too.
My personal feeling is that if you're going to make the switch from 939/DDR/AGP to (775 or AM2)/DDR2/PCIe, save your coin and do it all at once. None of that stuff is getting more expensive in the long-term.
As for the DX10 thing, people keep forgetting that DX10 is for Vista, something I have no intention of converting to in the next couple of years. No typical working application will require it for a long time. Even DX10 supported games aren't going to be the norm for quite a while.
Now, for my own personal situation. I have been accumulating pieces/parts for the last few months and was about to put together:
Antec Nine Hundred case
OCZ Powerstream 520W (but may use a PC P&C TurboCool 510 I have instead)
MSI K8N Neo2 Platinum (skt 939)
AMD 64 X2 4400 (plan to do a little OC)
2 X 1GB OCZ PC3200 Platinum Ed.
Creative X-Fi ExtremeMusic
...and an X850XT from another system I have.
I've had the motherboard for nearly a year now, and the X850XT was always meant for it. I am not a gamer but I do CAD and some graphics work, and I love screen "Real Estate." I'd been watching for a SONY SDM-P234, but the supply dried up when I blinked. Meanwhile, I was offered a NIB Dell 3007FPW, with warranty, for $750. Couldn't turn it down!
Unfortunately (or perhaps, fortunately), native resolution on the 3007 is 2560 X 1600, requiring a dual-link DVI connection (not to be confused with dual DVI). Almost all DL video cards are PCIe--few available as AGP. I was planning on going to C2D later this year, once the Quads were more available (driving the C2D prices down), and going to an R600 class video card then (all that stuff is DL). Problem is all this is either bleeding-edge or not even available yet. If I did it right now, I'd opt for an nVidia 8800GTS, but that is strictly a PCIe and it'd drive a COMPLETE system upgrade I am not ready to pay for (mobo, C2D, DDR2, PCIe video). Remember, 8800GTS starts at $375 currently.
I stumbled on the HIS X1950PRO IceQ3 512MB Turbo card at NewEgg for $300. The non-turbo 512 was $275, and the good cooler used on the Turbo version is easily worth the extra $25, even if it didn't clock any faster (Turbo runs @ 620/1480 vs. 575/1380 non-Turbo). I went with the 512MB because of the amount of pixels I am driving, and it was only $50 more than the Turbo 256MB version.
Anyway, bottom line is that I needed this much card to run the monitor, the price to upgrade to this card was less than the PCIe card I would have chosen (to say nothing of the requisite associated hardware), and I've bought myself at least 6-10 months of time. Everybody's situation is different, but I feel high-end AGP stuff will be a viable market for another year or two.