Of course you all have seen the new transparent menu bar, the new dock etc…Here are more details on 10.5 improvements:  

Imagine the sample on the left as your current display, and the sample on the right as a display with four times the amount of physical pixels. Both use the same amount of space, but there is a very noticeable difference.

All application and document icons will grow from 128×128 pixels to 512×512 pixels!!!

All apps go “brushed”:
Aqua applications (non brushed metal) like System Pref, Apple Mail and Preview became brushed :p
iChat and Finder remains brushed…

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