My PS5 will be through Amazon and the Anaconda directly through Microsoft or amazon if I can't get it through them, probably Microsoft because I have $180 in credit.
Last time Amazon sent me an extra PS4 day 1. Will never happen again but hey it was definitely nice.
Somewhere that does a midnight opening so I can collect them by hand and not be at the mercy of awful U.K. post. I had a DHL parcel that went out for delivery every day for four days and still never made it to me recently. I had to drive to the depot on the fifth day and hand collect it.
Gamestop if they have a good trade deal for the current gen systems. They had really good trade deals here and there for my base systems when upgrading to a One X and Pro. Just as much or a little more than I would have gotten if I had sold them myself.
Probably Gamestop. I'll pay a on them a bit at a time starting in the summer, then I'll trade in my X1X towards Scarlet and PS4 Pro towards the PS5 a few days before they release to finish them off.
If the backwards compatibility just plays games exactly the same as on the PS4 then I won't bother at launch but if I do then probably just through Amazon
I prefer Best Buy but they never do midnight openings at my local store. It will likely be GameStop or wait until the next day. There are two Gamestops here so I expect one of them to close and the other remain open.
EDIT - That's assuming they are 100% BC. If they are not, then I'll probably wait until I've played through the PS4 exclusives I haven't finished yet (I haven't even started GoW or SpiderMan despite owning them. I just don't have the time). I'm hopeful both machines will be fully BC so I can just move my backlog pile over.
Pre-order from local store with "pay on pickup" -option, so that keeps order active up to one week from day-1 and give me time to read reviews and better evaluate if I actually have need for the damn things.
Probably a PS5 from Amazon. I think I'll hold on an Xbox this time since i beefed up my PC. and have three years of Game Pass. Feelin' great about next gen.