I think the best advice I can give, based on the reviews that are starting to come out, is simply that if you don't want to want a new iPad just don't look at one.
I struggled after the event to put the right words together to describe the display and a week later I’m still lost for the proper analogy. The only thing I can think of that comes close is comparing it to the first time you ever saw an HDTV. Remember how startling it was to go from one of those giant standard definition projector TVs to an HDTV? That’s what this is like.
Reading on the big retina display is pure joy. Going back to the iPad 2 after reading for a few hours on the iPad 3 is jarring. With bigger pixels, anti-aliased text looks blurry; with smaller pixels, anti-aliased text looks good; but with really small pixels like these, anti-aliased text looks impossibly good — and what you thought looked pretty good before (like text rendered on older iPads) now looks blurry.
Jason Snell of Macworld:
Users of the iPad 2 shouldn't fret: Their iPad investment is certainly good for another year. But they might not want to look too closely at the new iPad's screen. Once you get a load of that Retina display, it's hard to go back to anything else.
And this, again from Gruber's review, doesn't bode well for me and my clients in my day job:
Websites, too — most graphics and images on the web are behind the curve, as of today. Text looks great in Safari, but non-retina images look slightly blurry. The iPad display is so good that it shows, like no device before it, just how crummy most images on the web are.
So please don't show me your new iPad. I'm sure it's amazing but I'd prefer to stay in the dark until my bank account is in a position to withstand the unnecessary purchase of the new iPad.