A few days ago, AMD did a live Q & A, answering questions about Ryzen, the future of Ryzen, old FX cpus, where are the ITX motherboards and lots more.
Timestamp from videocardz
1 : 10Where are Mini ITX motherboards?
3 : 40Which Ryzen is good for you?
6 : 20Info on Ryzen Raven Ridge APU
7 : 39When is AGESA 1.0.06 going public?
10 : 36Optimiziation for Ryzen in upcoming games
15 : 19Why Infinity Fabric runs at the same speed as DDR memory?
17 : 12Ryzen/Threadripper clothing
17 : 50How to choose Ryzen motherboard
19 : 43ASUS ROG Ryzen gaming laptop
20 : 18Does Freesync 2 work better with Ryzen 5&7?
21 : 15What to do with FX 8350?
22 : 23Market adaptation for 8-core CPUs
24 : 53Features of AMD chipsets
26 : 09Forward compatibility for AM4 socket
29 : 50Thunderbolt support
30 : 17Why Threadripper and not Ryzen 9?
32 : 10Ryzen optimization for higher clock speeds
34 : 03Linux virtualization
34 : 55Will BIOS updates continue to increase memory clock speeds?
36 : 57CPU pins bent resistance, why PGA instead of LGA
38 : 14Access to memory timing for overclockers
38 : 38Is 1500X the sweet spot CPU?
40 : 42What optimization can be made to Infinity Fabric?
42 : 00Opensourcing PSP code for Ryzen
43 : 21Ryzen 5 vs FX Series
45 : 52Support for developers in optimization for Ryzen
47 : 48ITX support (again)
49 : 07Ryzen is the best CPU because…
52 : 59Is inter-CCX latency a problem?
54 : 46What’s SenseMI
https://www.twitch.tv/videos/146654315
I'd go with a 650 watt, to give plenty of room to grow. Keep in mind, this is one of the few components you can really future-proof. Also, make sure to buy from a reputable supplier (Corsair, CoolerMaster, ect.)