With POS imminent, is building a rig right now a terrible idea?

What are all your thoughts? I'm thinking about building a 6 or 7 RX480 machine to mine ETH but I'd like to have a fallback altcoin if ETH tanks or for when they switch to Proof of stake. From what I've seen, LTC, XMR and Zcash aren't even profitable unless I'm doing the calculations wrong. I only pay about .7 kwh so my electric is on the lower end of the spectrum.

Any advice would be great, really want to get into mining but want to be smart about it. Thanks!!

Jon