I have owned and still own quite a few Android tablets...
Samsung Galaxy Tab 2 7.0 Student Edition.... (still own it)
I couldn't pass up the deal for a GTab, keyboard dock, and card reader for $250. It wasn't the fastest tablet around, but the functionality of the Tab with the keyboard dock was terrific. To be able to have a quality keyboard (and bluetooth mouse) was great. The keyboard dock had a 3.5mm headphone jack, so I attached speakers. This turned out to be a nice little micro-workstation.
Kindle Fire HD... (still own)
16GB 7" model. Rooted it, installed Google Play and Nova Launcher. I use it as a color ereader(comic book scans and vintage magazines and catalogs) and generic Android tablet. I use it when my iPad and Surface RT aren't easily accessible. Play some games on it. Has the best speakers of any tablet I've ever owned. Beautiful screen. The official smart cover is also the nicest tablet cover. The cover doubles back on itself to form a solid stand. Will occasionally watch videos on it.
Polaroid PMID701i (still own, about to give away)
I've owned this for a while. Picked it up at Big Lots for under $100. I wanted a tablet that had Ice Cream Sandwich so that I could tinker around with. Battery life to poor, screen quality too poor, and got surprisingly warm. But it was fun to tinker with.
Kindle Fire (no longer own)
I loved the skinned interface, the design of the hardware, and quality of the screen. Traded it in towards the Kindle Fire HD.
Nook Color (no longer own)
Bought it back before the Kindle Fires were released. For $150 and rooted, it was a terrific value.