[Edit] As per jbadams polite pointer - here's a summary.
I've gone from 2048x1024 "plain ol' texturing" of terrain and cloud/illumination to normal mapped goodness at 4096x2048. I'm quite chuffed with the results :)
I'll try and push up a video of an Earth-like planet orbit as soon as I can.
http://dominion.maksw.com/2013/01/29/high-resolution-worlds/
Cross-linking is fine, but it'd be appreciated if you could also put in a brief summary of the entry or even just paste the first paragraph so we'll have an idea what we'll be reading if we click the link. :-)