Here are some key features that should be in the next Playstation:

1) Updated Playstation Network

2) A New TV & Video delivery service that gives you the chance to subscribe for tv networks like Fox, Disney, CBS, NBC like IO digital cable.

3) Beyond high def graphics.

4) more in depth and virtual gaming

5) online service that supports play online with people from more than 20 countries

6) 200 GB

7) Bluray ( of course)

If that sounds crazy, give me your ideas.

It shoudn't come before 5 more years :P
That's my number 1 feature !

I would add:
1) at least 2, better 3 or 4, general purpose PPC cores in its version of Cell and at least 4GB RAM, better 8 to benefit also its use as a home PC with personal productivity SW
2) full BC with PSOne, 2 and 3
All this in 4 years should cost to build, even since launch, less than what it costs now to build PS3, and this leads to my 3rd point:
3) a launch price (sustainable, at most with $100 loss per console, but better with no losses at all, not wildly under price like PS3 at launch time) at most $400 for the lower end model and at most $500 for the top end one.

Obviously, if they don't like suicide anymore, simultaneous worldwide launch, never again clumsy and sorry figures like limited launch due to blue laser shortages and such other things.

Drink holder
Wheels
Carrying handle
Towel rack

Eliminate Region-locking all together. I know it´s nearly impossible, but I want it.

They only have it for movies, though they allow you to download other content from foreign PS stores, which I think is pretty nice from Sony

anyway, it needs BC, a 6 disc changer, and to be bundled with FF XIV

@shameless, lol!

Full PS1/2/3 BC
Hopefully a traditional controller
More KB/Mouse support in games
Stick with region free games
PSN with more rare ps1/2 games (don't make me pay $80 for Suikoden 2)
I am guessing they will probably stick with blu-ray, so a much faster drive.
Probably legal reasons, but let me buy stuff off the JP store with a US credit card.

Honestly as far as hardware, I'd say they did a lot right with the PS3.

hopefully it will stay similar in architecture to PS3(cell)for 3rd part developers,,so that they will be familiar with PS4,,,,,,maybe multiple cell processors like 3 cells?

It will get home from start.