I don't think any current games or software need more than a pair of 5970s (or even a single for that matter) for a single monitor
My thoughts on the recent video cards is that ATI didn't expect the 4XX series to be as good as it was, so they rushed on the 6XXX series. I also kinda think that Nvidia boosted the power of their 4XX series specifically to be able to compete with the ATI 5XXX series. I mean come on.. they couldn't have purposely planned to have those kinds of power draws and heat outputs could they?
I mean yeah, the 6XXX series has some added features and tweaks, but I think that the next generation will receive a die shrink and the leap from 6XXX to 7XXX will be much bigger than 5XXX to 6XXX. I'm thinkin late Q4 2011 for the 7XXX...?
I'm also thinking that we will see some 120 and 240 hz monitors(following the trend set by HDTVs) and I'm going to wait to see how that plays out for connectors and cables and such. I really want 3x 240hz 27" 16:10 IPS(or equivalent) thin bezel monitors when they are available
Also, slightly off topic perhaps, I really want to love ATI cards, but their garbage drivers are making that hard lately, so I may be looking at the 6XX Greens instead of the 7XXX reds. And yes I say ATI... I am ashamed to say I own anything made by AMD.