need help building a 2000ish euro Workstation for 3d rendering and FX work

If you're doing things like 3D modeling and rendering, you're going to want a workstation class GPU. On the Nvidia side, its the Quadro series, on the AMD side, Firepro.

The top quadro GPUs are the 4000, 5000 and 6000, at around $700, $1500, and $3000 respectively. Here's a chart comparing them: http://www.nvidia.com/object/IO_11761.html
The 6000 is probably out of your budget, but the 4/5000 will do you nicely depending on how much you spend on other components. If you know you need more vram than that, the 7970 has 3 GB of GDDR5, but it's designed for gaming, not professional render work. Sapphire is coming out with a 6 GB 7970, and there will probably be some kepler GPUs with tons of memory, but not for a little while. If you really need more than 2-3 GB of memory it'll be tough to come by.

Basically, at the same price point the Nvidia cards have better specs so I'd recommend one of them.

If you're stuck on AMD, go for either an 8-core bulldozer or a phenom II x6 since you can probably use all the cores. If you can be convinced to jump ship, the 2600 will do you nicely (or you could wait for Ivy Bridge). If you want to spend more money, an SB-E chip will give you tons of power. Or you can go for the 3820, which is a socket 2011 CPU so you get all those features and the option up upgrading to SB-E or IB-E The problem is the motherboards will be more expensive.

Get as much RAM as you need, it isn't terribly expensive compared to other components. You might want to look into ECC RAM, but that's mostly used in servers, so I don't know if you'll need it. If you want that, you need a motherboard that supports it.

If you aren't overclocking, you don't need a super duper cooler, the stock one should be fine.

And as for power supply, the corsair ax650 is 80+ gold, fully modular, and should have enough juice for you.