The Nook Color is pretty different from other Android devices - it's locked down by B&N and they're planning on opening their own app store for it. It's also missing menu, back & search buttons, found on every other 2.x device.
In addition, it isn't being marketed as an Android device.
If you take a look at the Barnes & Noble site for the Nook Color, you won't find a single mention of Android - it's pretty clear that they do not intend to be a part of the Android ecosystem at all, unlike the Droid.
You mean the Samsung Galaxy Tab? It has the Market. Perhaps the upcoming Motorola XOOM? Yep, it has the Market.
The only two exceptions I can think of are the Archos tablets and Notion Ink: Archos doesn't fulfill Google requirements, and I don't know what the problem with the Adam is. (Obviously, no-name Chinese tablets also don't get the Market, but that's not a huge surprise.)
I'd have phrased it the other way: the only two exceptions that I know of that can access the market are the Galaxy and Xoom. One of which isn't available and the other is almost a poster child for the uncertain upgrade path problem.
No-name Chinese tablets aren't a surprise, but the fact that they get casually included when people talk about ecosystem devices and sales is part of the problem.
besides devices that can't access the store are those with limited access. Like the HTC Wildfire and the other devices with screen resolutions lower than 320x480
Someone should probably point out this is a good thing.
It's exactly how Apple does it with the iOS platform - some apps are targeted exclusively at the iPad, and the App Store filters on screen size. Some people say this is fragmentation, but I think a better term would be specialization. All platforms do it - the question is how easily the platform lets deal with it. I think Android does it pretty well (as does iOS).
If you want to target the low-resolution devices then you put it in your manifest and it will appear in the market.
I'm sure the same thing will happen with Google TV - some apps will be designed exclusively for Google TV, and so won't appear for phones. Doing anything else would kind of miss the point of the market!
(It's also worth noting that many Android apps have download links from a website, so if you really, really want to use an app that isn't designed for your device you probably can)
...such as?