After having used a NookColor for a month, I can say that it beats all other dedicated ereaders hands down - particularly for gaming uses. I also work in a public library where part of my job is to use every ereader on the market - and the NookColor spanks each one of them.
eInk displays will not work well for gaming products. The display simply cannot reproduce the graphics required for most gaming books. That takes out ereaders such as the original Nook, Kindle, Kobo, etc.
I've been reading downloaded PDFs from sites such as Paizo, WotC, and Steve Jackson, and all are great. You can zoom or adjust the page to fit the screen. For my vision (which is pretty terrible compared to just about anybody), this is sufficient.
The NookColor's Internet access is WiFi only (no 3G model available as of now). Its is not compatible with Silverlight, which means that there's no WotC character builder and the compendium doesn't work. But for reading PDFs, it works great.
If you have any other ereader questions, let me know. (I've used about all of them.)
Retreater