Hi Matt
If what you are using it for is serious photo and video editing where the color has got to be perfect, I'd say go ahead with the 30" ACD. Try to find one at a discount if you must like maybe refurb from Apple, but it's still a really great display for serious Photoshop.
I have only its little brothers the 23" and 20" and the color accuracy is phenomenal. The screens are perfect in every way except price. I put a Spyder on them and needed almost no tweaking to the color profile.
You can soon forget high price but will forever be cursed by a lesser display.
"It's got the same panel" many will say. Or does it?
Panels are GRADED before being sold to monitor companies.... guess who get the best ones? The companies with the most expensive monitors!
There's more than a panel in a Display too. There's cases where "the same panel" did worse because of the interface board having analog and digital circuitry instead of digital only (like ACD).
"Older" Technology?
Sure. But S-IPS is still one of if not the best for color accuracy. As well as for having a very wide viewing angle from any direction.
Oh, but LED backlights are coming out!
Well, the florescent bulbs still work and do really well for years. The ACDs are Bright with a capital "B" if you want them to be and Apple has got the color just right.
Mini Display Port?
No, the next one will probably have that. It might have a gloss screen though. You will have to wait a few months or maybe only weeks to find out.
Matte screen?
The 30" ACD still has one of those too. Will its successor?
If you're buying a new Mac Pro and want a Huge, Color Accurate, Extremely Sharp and Clear display that's certified for color accuracy the ACD is still pretty hard to beat.
As a bonus, it integrates well with a Mac. Stuff like turning the Mac on and off with the monitor button, the monitor light winks gently when the Mac is asleep, you know, little insignificant stuff.
I'd say get one at Apple's Refurb store on their website. At $500 off list price, you won't feel bad if the new one comes out next week and you could always use it as a 2nd monitor (that can't be MiniDisplay Port)
Have Fun,
Keri