Pretty much that. Got it as a gift, a Nook HD 7 inch. It's got 4 gigs of space, if that means anything. I installed most of the apps that I have on my phone on the tablet, threw in some ebooks, streamed Netflix, but I feel like there's more to this thing than I'm using it for.
Technophiles of Hubski, unite. Meanwhile, I will keep butting my head up against this Calculus. Numbers suck, yo.
I have an iPad, so my suggestions are pretty iOS specific and may not all be available for Nook, but hope it gives you an idea of potential: 1. Reading pdf facsimile eBooks from Gutenberg and elsewhere (though they require quite a bit of guts to render - my iPad 2 struggled, but my iPad Air manages much better) - I much more enjoy the original scanned pages than text-based versions 2. Paper by 53 - a simply wonderful drawing app that lets even people with zero talent or training (me!) create something actually usable. I wrote and illustrated a children's book, and also made graphics for a work presentation using it. I'm sure there is something similar for Android apps 3. Reading news - for this my favourite app is now Zite but others such as Flipboard are also good 4. Writing - I have a Logitech keyboard case, and it's a very portable, very focused experience, as you can't so easily "move to another window" as you can writing on a laptop 5. Video editing - I recently discovered that iMovie can edit native files from my videocamera, so I'll be doing more of that for work and play 6. Watching video - I subscribe the the BBC's iPlayer app which has a vast amount of content, plus I watch YouTube on it 7. Games - interestingly, despite being a major iOS gamer on my iPhone (I even have this website - http://www.rpg-site.com) I barely play on my iPad. But certain games like card games/patience are perfect on it 8. Recipes - I use the http://www.pepperplate.com apps on both my iPhone (where the shopping list is great) on the iPad (where it's great as a cookbook in the kitchen) and on laptop, where it's great for aggregating recipes
I have wordpress on my tablet and I use it as a laptop replacement for some of my blogging activities. It's also great to use Trello for project management on a tablet, it's really easy to use. Other than that i use it for games and stuff. I think if you plan to use it as a laptop replacement, which a 7in isn't really geared for that, you'll have different apps than if you want to use it for entertainment. Typing on a 10" (with blue tooth keyboard) is much more practical. So, think about what you want to use it for and then it will help you decide what apps to download.
The ultimate conclusion i reached after having a nexus 7 was that tablets are ultimately pure consumption devices. They don't fulfill any need for me, just entertain.
Look up how to install a custom ROM on your tablet, if you're into customization. If you're not, then there are other projects you can use it for. You can construct multiple projects using Bluetooth and Arduino: anything from remotely turning on lights with your tablet, to using the setup for an automatic coffee brew. Check out Instructables.com, they have tons of projects like this.
I've had my Kindle Fire for two years now. I use it for reading. And reading. And occasionally reading my rss via Feedly if my phone dies. I have an iphone so the minor differences in back button and keyboard annoy me. Probably because I don't use the Kindle enough. My mom has an iPad and she loves it but she uses her iPad as I use my computer. Twitter. Reading articles. Getting emails. Browsing facebook. Looking at recipes. Listening to podcasts. And reading books. I think it's great for that but I like commenting over retweeting and that takes a keyboard, IMO.
The top 2 things I love my tablet for are (1) reading Graphic Novels and (2) reading the internet. I also have a Kindle, but the small grayscale screen can't handle graphic novels. The tablet is great for them. Also, comic books, if you're into that kind of thing. Both Marvel and DC have apps, and there are a lot of graphic novels available for the Kindle app. I do have a Nexus 10. I'm not sure whether 7" is too small for graphic novels. I also really enjoy the tablet experience for reading internet reading-things. News and blogs. Most news sites have apps, and for blogs you can simply make bookmark shortcuts. At first I thought news apps were redundant, but I really do find their experience better than the browser.
Calculus is kinda awesome, though. Yeah, it's a shit-ton of BS identities but calculus kinda makes the world click. Tablets? Yeah, you got me. I damn near bought an iPad Mini but not because I have any use for it, other than this one and this one. My wife will probably buy one for EMR (Electronic Medical Records). So yeah. Not a deep electronic music gearhead or doctor? Dunno what to tell you. I own two Kindles but they're both eInk. All they're good for is reading books, something I consider transmissive screens to be pretty terrible for.