I use the Nexus 7 2012 for:
Online banking
Google Maps
Calculator
Quick note taker when laptop is inconvinient.
Google Voice
RDP client at times, but it isn't anything hardcore
ssh client - not optimal and less efficient than via putty, etc on Windows or simply using Linux, but I have the option.
Gas Guru app is nice.
Other "deals" apps.
Grocery store checking.
Email
Web browsing, although it is just as fast as a laptop with an HDD and ULV CPU.
Some videos, although I hate the flash auto stop.
An inconvenient picture taker.
Trying to find a keyboard I can love and a proper GPS app that is convoluted to use.
When I find a use for it, Where's my Droid might become useful as well.
Reading probably something I could employ the Nexus to do as well, but I haven't done any reading on it yet.
Haven't done any gaming on it yet.
Given that I got it for $130 as a refurb, it is quite useful as a supplementary device, but certainly won't be replacing any PC, laptop or desktop, especially since it soft bricked itself. Curing a soft-bricked Android tablet requires a PC.