What you think of this?

Looks good. I can't comment on pricing since I'm not going to enter all those values into a converter. The two things I'd take note of is that you probably don't need the sound card unless you have some really nice speakers, and that the Raptor drives are somewhat overrated. Here's something almost as fast with a heck of a lot more room, and should be cheaper than the cost of both your drives:
http://www.newegg.com/Product/Product.asp?Item=N82E1682...

You'll have to find it from a European vendor, though.

One problem I'm seeing from the off is that the motherboard only has two RAM slots, which doesnt leave much room for expansion.

I've also been told that 2GB RAM isnt enough for the next generation of games, but I'm wondering - is 2GB of superior RAM comparable to 4GB of average RAM?

The P5N-E SLI actually has 4 RAM slots. And its a great choice of MB. Great for overclocking.
You can easily step down one size is PSU - something around 600-650 should be fine unless you really intend to use 8800GTX x2 in SLI.

2GB vs 4GB RAM - not as big an influence on gaming performance as higher CPU/GPU power. 2GB is excellent to start out. You can always add more RAM once you find a game where 4GB has a big influence on performance.

I agree that Raptor drives are over-rated for gaming. You can get 95% of the performance and 5x the storage for less money with a Seagate Barracuda 7200.10 Perpendicular Recording HD.

If a game will actually utilize all 4GB of RAM, I would take a guess that it having 4GB of average RAM would be much better than 2GB of faster RAM. In my experiences, faster RAM mostly helps with getting a better overclock. I haven't really heard of any games that will benefit much from 4GB, though. I would imagine that 4GB won't become the standard for another couple years.

If this is your mobo: http://www.newegg.com/Product/ProductList.aspx?Submit=E...

Then it does in fact have room for 4 x 1GB DIMMS, which means you can upgrade to 4GB later. Something to note, however, is that this board isn't very good for SLI (which you aren't using anyway).

Here's a very good motherboard that's less expensive and should suit your needs just fine:
http://www.newegg.com/Product/Product.asp?Item=N82E1681...

Here is a review that compares the P5N-E SLI to some top 680i boards. It shows the P5N-E is actually very good - even is SLI.
Asus P5N-E SLI and Striker Extreme motherboards