Mac upgrade question

I'm currently working in FCP 7 on a Mac Pro (Early 2009) running OS10.6.8. I edit and encode SD and HD video for DVD and Blu-ray.

I have the option to upgrade to a new 27-inch iMac with Retina 5K display. I'd probably go for the best spec I can afford.

Or... would I be better off waiting for the new iMacs to launch in 2017? I also have a lot of Firewire 400 and 800 external hard drives, ranging from 2TB to 6 TB. Will these be OK with a new iMac?

I'm rather confused about the best way forward. Would I see a significant speed improvement with a current iMac, or should I wait a few months (I'm guessing!) longer?

Thanks in advance

It depends how long you can wait, as the current version is over a year old. But I have a friend with this iMac and it's pretty fast. The problem with waiting for the next thing is that there's always a new thing coming. If you need it now, buy it now.

Current iMacs do not have FireWire ports and new iMacs will probably use USB-C, so you'd need adapters regardless of which one you chose.

My software:
Pro Maintenance Tools - Tools to keep Final Cut Studio, Final Cut Pro X, Avid Media Composer and Adobe Premiere Pro running smoothly and fix problems when they arise
Pro Media Tools - Edit QuickTime chapters and metadata, detect gamma shifts, edit markers, watch renders and more
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Thanks Jon. I'll wait until after Christmas and see if anything gets announced. But I doubt it. Any recommended adaptors?

Best to wait and see what ports the new one has if it's out by then. If it's just got USB-C you'll need adapters for almost everything. But for the current version I don't know if you'll need anything more than Thunderbolt to FireWire. Apple sells them for $30: [www.apple.com]

My software:
Pro Maintenance Tools - Tools to keep Final Cut Studio, Final Cut Pro X, Avid Media Composer and Adobe Premiere Pro running smoothly and fix problems when they arise
Pro Media Tools - Edit QuickTime chapters and metadata, detect gamma shifts, edit markers, watch renders and more
More tools...