Okej so im going to buy parts to build a computer, now i am stuck in the CPU choose.
Is it more worth it to buy a AMD Phenom II X6 1090T with 6 cores aka HexaCore or should i buy a cheaper one? the Phenom costs about 150$, think its cheap but i svck at these things.

Depends on what you want to do with it. What motherboard/RAM are you getting? If you just plan on gaming, then a quadcore (or even dual core) is fine. But if you do video editing/encoding then more cores the better.

oh ok. i am actually doing some editing and stuff^^ the Motherboard my friend will help me with and the RAM do i need a special sort for a 6 core CPU?

Well as long as you are getting DDR3 and the motherboard is AM3 then the AMD Phenom IIx6 will work fine. But I use a AMD Phenom IIx4 955 overclocked to 4GHz and I do a lot of encoding and it still works amazingly.

Unless you need a HexCore, I'd reccomend sticking with a Quad Core. We can't yet do 6 cores on one chip at the same speed as 4 cores - they just get too hot! Unless you'd actually use 6 cores often, stick with 4, you'll get more bang for your buck.

ok.
This is how the planned computer will look like.
The Phenom IIx6 hexa core 150$
16Gb corsair XMS3 vengeance 170$
GTX 560ti 200$
thats the beginning but then ofc i will find a Motheboard Am3 and maybe make the corsair to 8Gb for 79$

16GB of RAM is a bit overkill unless you are running a RAMdisk. 8GB is still overkill, but I actually plan on getting 8GB soon for running a RAMdisk. Also make sure you dont skimp on the PSU.

Ye but i think that 4Gb of ram is getting a bit... ye you know, many games are starting to take like 3Gb ram to run and such. and who knows how much skyrim will need^^
I also need to have alot of recording programs in the background, so atleast 8 GB for me is the minimum.
The PSU will be about 800W but i will wait to buy parts until Skyrim comes out.

Corsair is good brand to buy for PSUs. I build all my PCs with Corsair PSUs. Make sure you get a 64bit OS. And Skyrim wont require that much RAM, but more will always help. Oh if youre waiting to buy until Skyrim comes out, just know that the AM3+ bulldozer class CPUs come out this summer so I would wait for those. They wouldnt work on AM3 boards.

So i have heard, i've been looking at the corsair PSU's, good price and everything. powerful to.

I'd suggest an Intel Core i5 2500K over any AMD processor. Its around $30 more than what you're considering, but is a good deal faster. I like my Phenom II X4 955, but I bought it two years ago when it was still competitive. It just doesn't make sense for a new build since the release of the Sandy Bridge processors.

AMD CPUs are not advisable for video editing and DVD/Blu-ray authoring.

AMD processors, like the Phenom II X6 and even dual hexa cores, like the Opteron 2431 are way outclassed by Intel i7 processors, because of the lacking SSE4.1 extensions that are extensively used in CPU intensive tasks (such as video encoding/transcoding).

If you can afford it I would highly recommend i7-2600k, or at least i7-950

And if you will be working with a 64-bit editing apps (such as CS5), ignore the naysayers about the RAM. The more RAM, the better.