IE8 seems not so bad today, but without any support for html5, css3, canvas, video or websockets, what will you think 10 years from now ? That it sucks: it will force you to have Flash/Silverlight fallbacks to do something as trivial as plotting a graph or displaying a video. Yet many XP users will still be using it, so you will have to support it...
MS with IE8 (an IE9) are actually trying to make their browser standards compliant and while we might not like the pace of the behemoth, it's moving in the right direction and this is a good thing.
2010 is a much different landscape than 2005 as far as the browser market goes as well; MS/IE are no longer the dominant juggernaut that can attempt to dictate standards.
More than anything IE releases are tied to MS's OS releases - IE8 has become the largest slice of the IE pie because of Win7, not because of features or any push by MS. As MS increases their release cycle of both browsers and more importantly, OS's, the likelihood of a IE6 repeat with IE8 is extremely thin. MS can't sit around on any version of a major product like they did with both XP and IE6.
If you also plan a bit up front and have a competent designer to help out with the css definitions and strategizing (like avoiding gradients for now, fun/cool as they be), it's really not that big a deal.
I'm working on a new site and I've literally done nothing other than have a designer help out with the CSS and the only difference between Firefox, Safari, Chrome and IE8 are css drop-shadows, and rounded corners. Purely cosmetic, unlike IE6 which if you didn't account for it could stop your app in it's tracks.
To me IE8, as much as I would never personally use it, is a huge improvement from IE6. Even over IE7 it's hugely better, easier to deal with.