Need advice on building my first selfbuilt PC

So I currently have a so-so laptop and a 6 year-old prefab desktop, and they're just not doing the job for me anymore so i've decided to upgrade to something with a bit more muscles.
I am however not very experienced with hardware and have never built my own pc before so i thought i'd ask here for advice.
Well, here goes:

APPROXIMATE PURCHASE DATE:Haven't really decided yet, but most likely sometime this month. BUDGET RANGE: $1100-1300

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Gaming, watching movies, misc.

PARTS NOT REQUIRED: I dont need anything but the pc itself, although i'm not sure if a new monitor is needed. (Currently have a 19" lcd)

PREFERRED WEBSITE(S) FOR PARTS: As i'm from denmark i'll most likely be buying from Komplett.dk (Komplett.ie for english version)

PARTS PREFERENCES: No real prefenrences.

OVERCLOCKING: Maybe SLI OR CROSSFIRE: Maybe

MONITOR RESOLUTION: My current monitor resolution is 1280x1024, but I wouldnt mind bumping that up with a newer monitor.

ADDITIONAL COMMENTS: Nothing special is really needed, although led's are always fun


Thank you in advance for any advice.

Well, I might upgrade my monitor at some point, since HD and widescreen is quite nice. Just not sure i have the cash for that right now though.

Very interesting, ty. Its something along the lines of what I've been looking at already. However, im just wondering. Is it worth it sticking with DDR2 instead of going for DDR3?

Yea, I'd like to be able to use it at least 2-3 years or more in the future, so maybe i should go for the DDR3.
And yes budget was in dollars.

Edit: Another question: Wouldnt a hd4890 be worth it over 2x 4850? From what i've heard they perform almost the same, and at about the same price. However, it seems like not all games are able to use the dual gpu, the 4890 is using DDR5, and at last you have the option to upgrade with another 4890 sometime in the future. I havent really been able to find many benchmarks for 2x 4850 though so i might be wrong.

2x 4850 will beat the the 4890 in many benchmarks for a similar price (or cheaper), but many people prefer single card GPU solutions because ATI drivers are *** and a lot of people have issues with vfire drivers. So, the 4850 is slightly better, but the 4890 is simpler (and as you've noticed, you can add a 2nd one in the future - however, if you don't add it within 6 months it will probably be outdated and you'll be better off upgrading to the nextgen gpu, see: dx11).

As for building the computer, it's like legos. Make sure you don't put too much thermal paste on your CPU (read a few articles, its not hard). Read the mobo manuel and it'll tell you how to plug everything in. The only tool you need is a screwdriver. If you're really worried, I'm sure there are some videos on youtube you can watch although I don't have specific links.

Most important thing to watch out for is static electricity. Just take your time and have fun. Don't hesitate to reread the manual or look something up if you're unsure.