Lol. I'll get in quick before K.Jack shits on 1366x768 screens
The 1080p screen is glorious. I had my concerns, mainly that text and icons would be too small, but windows is set to 'medium' which increases font and icon sizes so it's still readable.
Three main differences to consider - quality, real estate, and gaming. Whther they are important is subjective to you and based on what you need/want
Quality: the 1080p screen is significantly higher quality than the 1366x768 panel. It'll have better colour rendition, and much better off angle viewing - with bad 1366x768 screens you can barely get the entire image clear before the edges start to dim. That might not be important to you if you'll just be using it for web browsing or office stuff. But if you do any photo editing, you'll find it difficult to adjust colours or brightness because the screen will be inaccurate.
Real estate: the 1080p screen lets you fit more stuff on. 1366x768 is ok, but I tend to need most windows maximised or at least fairly large, so I end up switching windows. 1080p let's you more easily have an IM window open next to your browser for instance. Or in Lightroom, the UI takes up much less space, so more is available for my photos which is what I want to concentrate on.
Both of those can be mitigated if you plan to have your laptop hooked up to an external monitor some of the time - it'll be higher res, physically larger and most likely better quality.
Gaming: the 1366x768 screen Is about half the number of pixels as the 1080p screen. So the GPU will work less hard to drive it. Thatll give you higher frame rates, more detail, or more AA. Having said that, the 660m is good enough to play in 1080p at high details in most modern games, and you can always drop the resolution if you want - I find 720p looks ok scaled down.
Overall I'm very glad I took the 1080p screen, but only you can make the cost vs value judgement for you,
Don't worry about the 4GB version, you can easily upgrade the ram. It's strange that Lenovo seem to do different skus even within Europe. Eg in the UK they have two - i5 1366x768, or i7 1080p bluray whizz bang. In Germany they have a TV tuner built in..
I5 vs i7.. Dual core vs quad. Most games don't need more than two cores yet, but they'll probably start to more often going forward. likewise lots of apps don't need more than two cores unless you really do a ton of video encoding. It will future proof you to an extent, but personally I'd think the GPU will run out of gas before lots of games become CPU bound by the i5. If I could have had the 1080p with the i5 I'd have gone for it, but for me it was £150 to get 1080p, bluray and quad core, so a good bump in overall spec for the price.
(can you post a link to the products you are looking at?)
Edit: do Lenovo Germany only offer the lower res screen? Have you looked to see if resellers have other skus? with the two shown on lenovos site, I think I'd get the lower priced i5. 150 is a lot for i7 plus bluray drive
Edit2: lower priced version doesn't have a mSSD for caching, so that'll affect the price too. But you still have the slot so you can add one later if you want
(with MSI Afterburner)
