Sometimes, depending on the wireless printer you have, the manufacturer of the printer will have an app in the Play store that works perfectly. I have a Brother Wireless printer and they offer an app that works from my phone or HD+. You might want to look into that.
I'm looking to downsize and would like to get rid of my PC and just use my Nook. I don't do much except the occasional Excel worksheet and Word document. [...] What do you think of the basic idea of replacing the whole computer?
I recently migrated from pen and paper notebook plus laptop computer to (mostly) using a 10 inch tablet. Most days, I can leave the computer behind and do just fine with the tablet. The problem comes when I have to create or edit documents. When you mention "the occasional Word document", what do you mean? For reading, you should have no problem. For editing or creating documents, a tablet has real limitations.
It's certainly a very interesting idea.
1. Is there a better email app than the free one? Which one do you recommend?
K9 Email App. Available in Nook Store. It's very good. Also an app called Mailbox is going to be available for Android at some point of time in the future. It's supposed to be really good. It was a free app and Dropbox bought it for $100 million just 45 days after launch.
2. What do you think of the basic idea of replacing the whole computer?
It's a bold move. I don't think Excel and Word processing apps are fast enough on a Tablet to make the move work long-term. However, it depends on what you use them for.
3. What is the chance that printing apps will become good enough to be easily used with a WI-FI printer?
Please see the recommendations from other posters. I don't know much about this.