Totally agree with Nuke on visiting a brick and mortar store and look at the screen.
Movies/games will look quite good on both with the 27 " giving more space, However text not the greatest on 27", But a lot also depends on how close you sit.
Loved my Samsung 24" 1920 x 1200 (16:10) monitor/HDTV, excellent display.
From that I went to -> 27" Samsung -> 32" Samsung (Got my Eyes fixed so back to 24" 1920 x 1200).
For games/movies the 27" would be a good choice, for productivity the 24" 1920 x 1200 would be my choice.
Note: Recently went with a Asus 1560 x 1440 27" PLS panel - Love it. But really still some what expensive ($650 which Dell also has one around the same price). However, there is an Auria EQ276W 27" 2560 x 1440 ISP for...