Looked into the Denon and speaker setup and again look good. Lack of support for 3D is the only concern not that it is an issue now but thinking to the future.
Separates sound the way to go to get the best sound but I'm not well informed enough to know what I am looking for, and a fool and his money are easily parted
If you have the stomach for a seperates solution ...
I have a Denon 1910 and I love it.
I am sorry I can't advise on the 3D, but off the top of my head I would ask the question of how likely you will buy a 3D tv; personally I cannot ever see me getting one. (famous last word, but makes sense). Therefore, setting that aside (and assuming 3D compat amps are pricey - being new), I'll continue:
Hillskill is right in that your best quality will come from Seperates. This has been discussed to death in the AV Home cinema forum section and we've given it a quick thrash in the COD section too. We all know it comes down to personal preference, and that All in One systems can suffice, but there is no getting away from the fact Seperates can really impress.
5.1 is all you need; I dont know of any films recorded in 7.1 and do you really have the space in your room?
This leads me on to the question: what are your requirements? Good TV/Game sounds, good looks and beautiful aesthetics for the room, or even Hi-Fi quality? Does it need to Upscale?
I'll skim over the Hi-Fi stuff; basically there is only one amp that fits in the under £1,000 mark that gives decent HiFi sound and its in limited stock; everything else is over £1k when you get into Arcams and the like, and it debateable they're better until you're up at 2k mark.
Sticking with good Film/Game sounds, then often the Onkyo comes out well, but the Denon 1910 as mentioned by Hillskill is said to be a nice compromise; while providing lovely quality for the money - can be had very cheap these days.
As much as you can't go too wrong with the Denon, you msut appreciate they are often said to have a warm sound. Pair them with warm speakers and you might find it gets too muddy, you tend to loose clarity.
Best bet is to go test different setups in somewhere like Richersounds - if you're spending over £500, then its the least they can do for you.
So assuming you've bought a £300 AV amp (say the nice Upscaling Denon), you now need speakers...
Do you want floor standers at the front, or are they too big? I'd only advise Floor standers and shelf speakers if you wanted to paly Hi Fi (at any level of decency) (I'd increase your budget too if considering hifi). If the answer is no, then satelite speakers like the Kef Egg do the job just fine. If you're using tiny satelite speakers on the 4 corners, and assuming you get a bass box (.1 part of it), then you will definately need a good Centre Speaker - it can be the difference between a good setup and a perfect setup.
Kef and Morduant both offer good small/neat centre speakers that give not only the tweater speach clarity but a bit of mid too (other manufactueres offer them, but far bigger - where do you put them?). Your AV amp will have adjustable volume to each speaker in the setup menu, and you can ramp up the centre speaker on films where the speach is lost in the music/battle-scenes etc.
Baldster advises a good setup - solid sound and speakers that will last. The Kef 3005 offers a lovely centre speaker - you could get the cheaper 1005 set and source a Morduant Genie seperately. The Sony amps offer quality in the ES range, but the Denon would do the job - if you can squeeze a bit more from your budget.
If you're considering better amps, then you'd better buy decent speakers; then you better ditch the ps3 for Blurays and get a proper player - it all adds up; too muc IMO. The original suggestions above seem far more sensible.