Some thoughts:
1. I wasn't expecting 4E before 2009, since
a) WotC said that all major D&D announcements in the future will be made at D&D Experience
b) I believed them when they said just a few months ago that 4E is still a "long way off". (These probably weren't the exact words, but the basic meaning of what was said.)
Wizards certainly lost quite some credibility with me, but that's I think something they can live with. (See also: "Ending Dragon & Dungeon has nothing to do with an upcomming new edition." Sure.)
2. Am I understanding it right that the Digital Initiative (now called D&D Insider) will only feature 4E (and edition independent) content? Will it be launched only in the spring of 2008?
I would have thought that there would be a year or two of 3.5 DI time, and only then a switch. As I see it now, there will be two "entry barriers" to the DI: you must be interested in online content + you must switch to 4E. I'm sure some people would have tried a 3.5 DI (and than stayed for a 4.0 version), but won't join now.
The impact of this is probably not to big though.
3. My first impressions - based on the small tidbits of information available at this point - aren't that positve. It seems that the rules are getting "simplified" (in other words: dumbed down), that's not necessarily something that I was looking for. Also I'm not getting this whole focus on "encounters". It seems so gamey. And looking back at some of my groups, I know that we would have had lot's of arguments when one encounter ends end when the new one starts. (I never warmed up to the new adventure format either.)
But I don't think that I'm really Wizards target audience anyway: I'm absolutely not interested in any online content (at leats not the form Wizards seems to have come up with), and am even less interested in miniatures. (Counters, coins or dice are doing the job fine, for a fraction af the costs.)
I think my gaming dollars in the future will go to Green Ronin's upcoming A Song of Ice and Fire books. I get the first two issues of Pathfinder for my remaining Dragon and Dungeon subscriptions. I'll probably by the rest of the first AP if it's any good. (I don't have much doubt that it will be.) After seeing the first previews, I really liked the setting material Paizo came up with for their new world, but I'll probably hold my purchases of it untill I see the future of the Pathfinder line (3.5? 4.0? something completly different?)
4. I wonder whether there will be introductionary prices for the new core books. When 3.0 came out, the PHB, the MM and the DMG cost only 20 dollars for some time, not 30 as later. Such a step by Wizards would increase the chances of me buying at least the new PHB.
5. What's up with the two "preview" books? Will people really pay 15 dollars just to staisfy their curiosity? Maybe it's just me, but this seems a pretty lame idea.
Bottom line: Good luck to Wizards. What you came up with is probably not what I'm looking for.