Obviously, it's really subjective, but I think the iPad is the hands-down best tablet. That said, it's a lot more expensive than competing Android tablets, but you really can do everything you need to.
For Android tablets, I'd argue the Nexus 7 is tops, but it'll leave you desiring some extra screen real estate if you need to rely on it for productivity apps.
Brands aside, the best tablet will always be the one with specs good enough so you can multitask, play games, watch videos, do whatever you do on a daily basis without lags. All high end tablets are pretty much the same in terms of performance. Stick with the big names if you have the budget or go for less well known brands (e.g, Ainol, Pipo, Ramos) that perform equally as well.
I like my iPad Mini Retina for everything - especially watching videos. It too bad it does not have flash but still it been great!