Like in other threads, if you have the money, then go for the i7. Im not telling that as the i7 model owner (but i own one), but as a user. I would be satisfied with the i5, but since the Greece dropped the Euro down, i7 models were on stock with lower prices, than more selling i5 models, actually, there were about 150 dollar difference between lowest i5 vs basic i7....
back to the point, if you play games, you need to have 512MB video RAM. since most games let you play only on medium textures with 256MB VRAM... but, on CPU side, on many occasions, you will get about 20% increase in performance, the 266MHz difference, higher Turbo Boost and also another 1MB L3 cache will do the job. Actually, it is a acceptable increase in price compared to performance increase. BUT, if you owned C2D, you will notice huge boost even in daily tasks like Safari, Flash blayback (2.33C2D vs 2.66 i7, 90% vs 40% 1080p youtube video playback and smooth as silk!), its all about CPU core architecture, than frequency, then go for the i5 if you just want to upgrade... the 20% difference wont be a big deal after 3 years...
I have basic 1440x900 glossy screen, since there is a big problem to get the user options in my country, also it will cost me about 300 dollars more (damn you Euro!). But i saw one, its nice and clean, but more heavy on eyes during longer work, you need to focus more, because everything is smaller, i prefer the 1440x900 option, is great for 15" notebook, and i would buy it anyway, even if the high res option will be easier to get.