The Retina Display and LCD are the same, the difference is simply pixel density (same with big and small 480i/p TVs)

The N900 comes pretty close to the Retina Display for a product that came out a year before
The OLEDs are brighter, and have true blacks, but have a much shorter life expectancy.

Man, what I wouldn't give for a phone with an aluminium-finish, dual-core A9+SGX6xx, 1GB RAM, FMtx, Bt, WiFi, IR, HDMI, 3.5" Retina LCD and a 1700mah LiPo.
+Linux.