Djembe's pretty much answered most of your questions, but I'll throw in a little more information in case it is useful to you.
The V2S has had a deal going on at MilestonePC and GentechPC. The deals were basically for a free external hard drive and maybe free shipping.
As for the 2000/- Euro, I don't know where that was. But the F8s will definitely be cheaper than the V2s, which is going for ~$1750 right now.
It might also be a good idea to bump up the Asus global warranty for 2 years, which will allow you to use repair shops pretty much anywhere in the world. Of course, buying with most AmEx cards will do the same thing also.
One note about graphics: As you said, the 8400 is underpowered. However, the V2s has the 8600GS which is widely considered underpowered compared to the 8600GT (despite the intense flames from both camps). There seems to be some conflicting information whether the F8s will carry the GS or the GT version. This may be a factor, depending on how hardcore your gaming needs are. Overall though, I definitely agree that any 8600 will outshine the 8400.