Sunset

[Gforce]

A really quick setup but somehow it took 10 hrs to render. Probably has something to do with my crappy comp. (2.4 ghz Pentium 4 with 1 gig ram)

[tumasch]

Well, my comp is still crappier than yours (2 ghz pIV)

Can't say too much about the picture, I'm afraid - looks like some basic settings to me. Some focal point would have been nice, e.g. some (main)land or island or ship or...whatever.

[rcallicotte]

Water renders slower (notice the graininess there) and your camera is facing the sun.  Both of these things together will increase your render time.

Keep trying.  Maybe increase your Atmosphere Quality settings and do some cropped renders to test how long these would take.  Maybe move your camera around to find a compromise between direct sunshine and the some shadow.