I would've recommended the Samsung due to 1080p for gaming, but I would also recommend the D3000 because most of your usage will be SD, and the Sony is one of the best for SD. Not really sure how the Samsung fairs on SD tbh, but they're known not to be the best in that department.
The only downfall with the Sony is that its an old model, and 1080p is the future. Thats the only reason i would slightly lean towards the Samsung.
The W4000 is an even better choice than the 2, of course, due to the price difference. It got a very good review from *
If you can spend £100 more than the original £600, also consider the Samsung 32" A656. You can get it for £688 from dixons if you use the discount codes TV8 & SAVE20. Very stylish (better looking than W4000 IMO), 1080p, red glow and 100Hz.