I didn't know there was a Sony Outlet, so thats going in the bookmarks!
The last of the old warehouse stock is/has gone on the website, but dont forget that stuff can still be in stores. A chap tonight was looking at the Panasonic 520 in a 40in. I said that it probably wasn't the first thing I'd recommend, and the Samsung 6400 would a great buy, although a little more expensive. He agreed that picture was better (more on that in a mo), but at £429 it was a little more than the £400 limit he'd set himself. I offered to have a look in the back, to see what had been marked down (there isn't room for everything on the shop floor). Came back with a 40H6400 for £379 (same price as the Pannie). He took it. So there are deals that can be found - just ask when you come in.
I was testing the 5100 next to the 6400 to show the difference in refresh rate tonight, and the 5100/5500 did not come off well. there was a lot of blur. Remember as well that the 5100 is not smart and only has 2 HDMI's (the more the better), but its the refesh that could be better. The Sony from Currys is bascially last years W7, but in a cheaper case (we had the 48in). The R4 series are basic...
As for LG, it depends. If you bought the 575 series last year, then the Samsung 5500's blacks were certainly better, but the refresh on the LG was much better than the Samsung. The 6 series LG had much better blacks, annd a very decent refesh for a 100hz screen. Better blacks tend to mean a bigger price, I'm afraid.
Only just noticed a philips in the list. Havn't seen a Philips in store for two years, apart from a dot.com return - and it was pretty rubbish for the price.
Best thing to do is to go into a store and see what there, and ask about markdowns. You've got a decent list of whats out there, and the price you should be paying for what spec. Armed with that, you can see if your getting a better deal by buying a markdown. If you can get a really good TV for less than £400 (and I'm sure you can), at least you'll know what your getting.