It depends on what you want to to with your smartphone. If you want to play big games, to watch videos, to surf on internet and that kind of things where it is better to have a big screen (or a laptop...), then take the Galaxy. If you want a phone just to phone, a smartphone not too big but not too small, but also sometimes use MSN, GPS and rarely surf the internet and that you have a PSP to play games, then take X8. I think to remember than X 8 has 600MHz and Galaxy has 1GHz, and Galaxy has a "true" graphic card : a collegue play to Assassin Creed on it.
"Hello, did you try to turn it off and on again ?" Roy - The IT Crowd
Sony Ericsson Xperia X8 (10w34) with stock kernel + GingerDX v025
Battery drain < 1%/h (near 0.5% per hour)
Changed white to black housing