Is it worth it

No.

I don't think so. Higher memory only comes into the picture at high resolutions. 1GB is enough for a good game. What is the resolution that you game at?

Its better if you bought this:
http://www.jimmspc.fi/tuote/NE5X460HF1102?t=false

Beats a HD5850 in many benchmarks. And is a lot cheaper than the 283 Euro!

Depends --- if you are using a very high resolution (ie. MUlti Screens) with high 3d settings (ie. high AA, AF, etc.) then the 2GB. may prove useful but for most users the extra 1GB. will rarely be used so depends on your specific usage patterns and how much you have to spend on the build.

It is unlikely that you will find a situation where the 2GB will show any difference of the 1GB version. I would just save the money and buy the 1GB version.

Yes I Agree...