I am powering down as well, but not nearly as much, I only had about 500 Steem. I think converting it to Hive and then powering up is a good way to spend Steem, because in my opinion, Hive has a lot of potential. If I had as much Steem as you, I would definetly put some in a major coin. For both Ether and Bitcoin, promising times are ahead, but I prefer Eth.
However, I also spent a decent amount of Steem on dcity. It is a trading simulation, in which you grow a city by trading and buying cards. It's super fun, and you also build a not so small daily income. Plus, all purchases are tradable, so you can always sell these cards again to get your Steem/Hive back.