I spent the last weeks working on version 2 of my planet engine. At the moment i'm only working on the geometric part of it. No eye-candy: no real lighting, no textures, no particles, no additional effect.. only the spherical terrain engine.
You can view a video here:
http://www.fl-tw.com/Infinity/Docs/Demos/ITerrain_09Dec2004.avi
And some screens:
It features seamless transitions in space and between planets. I worked hard to reduce the floating point precision problems, and think it's starting to look good. You can zoom up to a few meters above the ground. The heights are procedurally generated by 18 octaves of Perlin noise.
The terrain engine is currently going up to 60 millions triangles per second when the geometric complexity is high, ie. at ground level. There is around 300k to 500k triangles per frame, but it still runs at more than 110 fps on my 2.8 Ghz + Radeon 9700 system.