First things first, Matrox is supposed to coming out with a new card next year specifically to address the VISTA gap they currently have, but from my discussions with them (just checked again to be sure) it's at least 6 months out, and likely a summer product IMO. So if you need it at the start of VISTA then you should look to other providers. IMO the ATi X1300/X1600 (depending on needs) would be a good starting point until the new generation of cards from ATi, Matrox, nVidia and SIS hit the marketplace and make better starting points.
As for the alternatives, it's adifficult question to answer because there's not enough good 2D comparisons out there. I was kinda hoping I could find a more recent review with 2D quality comparos and was waiting until I found something to confirm my thoughts with regards to the new generation cards befor replying to you, but they are truely few and far between and I have seen none with regards to the GF7 and X1K series cards.
The Matrox cards likely still do enjoy superior filtering on the analogue out as I doubt any other company has dedicated the ciruitry and effort to ensure quality similar to that of Matrox. The quality of the RAMDACs betweem ATi and Matrox are now the same (and nV with their G80s) and they are also now all the same speed so that part of the equation has been removed, but for colour fidelity in applications that can exploitit I'd stick with ATi for the entry level stuff, and then either ATi or nV for the high end since all three are now the same in that respect. But for digital/DVI out I doubt that there is much of a difference in quality, and if anything the addition of at least 1 dual link TMDS into each new VPU has tip the LCD advantage to ATi & nV. This of course doesn't seem to be your focus as like me you're running a good CRT.
I have found that the quality of the output from my ATi MobilityX700 , GFGO5200, the S3 Savage, Matrox G200 and Intel Extreme, ExtremeII and now GMA950 have all been solid on my P260 here at work (my only frame of reference for HQ 2D across lines [at home I switched to ATi and nV long ago because they wer also used for gaming]). I did experience one hiccup with the first of the previous Intel ExtremeIIs I received where no amount of convergence tweaking could focus the image, I had to send it back (thinking initially DAMN how did Intel F it up going to this generation?). Turned out to be deffective at some point (never did get a response from DELL about the cause, could've been board generated noise, or bad pins or something), the replacement was fine (and of course all my tweking to make it work meant it took me about 2 weeks to get me back to my baseline. I have used this P260 on the DVI-A and VGA connector for many of these cards as I swap systems often even using 2 computer hooked up at the same time and fliping back and forth between my desktop and laptop (kinda like a KVM).
IMO if you're looking for something immediately I would say that a good option is the X1300 series, which gives you full 10bit per channel support for geared apps plus at least 1 dual-link DVI. You may miss out on some features you may have come to enjoy like Glyph AA, but it's an unfortunate situation where the options are restricted and Matrox is taking a slightly slower developement path to ensure the consitancy of their products. I can't say I agree with this position as it means anyone wanting to move to the new OS loses out one way or the other, but I understand it, since for them driver development is an expensive proposition, whereas for ATi and nV the cost is spread out amongst thousands of times more cards.
I'd love to see a new Matrox card, and to me they're still tops in analogue 2D, but I wish I had something more concrete like a good review to back up that position, and unfortunately regardless of that, the option for Matrox+Vista doesn't exist until sometime well into next year. Unless you have to move to Vista, you might want to wait and see what is on offer next year, otherwise youmay have to move on to someone new.