I'm thinking about upgrading my comp as well but a bit more towards the higher end.

Right now i have a icore 7 920 2,6 Ghz
ram 3GB DDR3 1066mhz Ram
500+ Watt PSU
4850 1GB Ati radeon

While i tink that i could get a bit better Ram, say 6 GB of 1066mhz or 4 GB 1366 mhz, two 5770 ati radeon cards for xcrossfire since the upper gfx cards away out of my funding capabilities.

No point in waiting for Fermi cards as more and more info shows that they are nowhere near ati quality and efficiency.

The proccessor is imo good enough for another 2-3 years, or so i presume?

Unfortunately i will have to upgrade to a better psu to have my pc work without a hitch with crossfire. i suppose that a 850+ Watt psu will be suffice.

The Core i7-920 is currently way overkill for gaming, so no need to upgrade that. It should last you quite a while, though mid-range CPUs in two years will likely kick its butt.

I don't think you'll get much benefit from moving from 3 GB RAM to 6. The maximum standard for gaming PCs nowadays is 4 GB (mostly because the majority of game developers still develop for 32-bit OSes), but since you picked the LGA1366 platform for some reason, you'll have to settle for either 3 (a little under par) or 6 (way more than you really need). I'd just stick with 3 for now.

What resolution are you running at? If it's 1680x1050 or lower, you don't need to upgrade the 4850 just yet. If it's 1920x1080 or 1900x1200, then a single 5770 should do you. Or you could wait a few weeks for the 5830 and see if that suits your needs. Either way, don't use Crossfire.

In other words, the most you'll need is a video card upgrade, and then only if you have a high-res monitor.

Well when it comes to computers i prefer to have all my settings changed to high/ultra high and like to have minimum 60 fps. So i get upset when i have a good rig and games like Mass Effect 2 don't run properly when i apply AA above 8x. Or when i have to scale down draw distance in GTA 4 (yes, i know that the pc version is broken and not optimized, just like the force unleashed, but still). Oh wait, i want to play future games without hiccups, like crysis 2, that's why i'm thinking about crossfire.

Right now i have a very old monitor that cannot go above 1024x768 res but i plan on buying a new moniter with a tv tuner (why have two seperate when you can have 2-in-1 with all the bells and whistles?) that goes to full HD

I play Mass Effect on an HD 5870 with a Core 2 Duo 2.4 @ 60FPS (vsync) with a resolution of 1920 by 1080. My suggestion is to go for a good single card because crossfire adds a little latency and doesn't always scale 100%, so a 5870 will be more consistant even if its a little slower in some benchmarks and that leaves open the possibility of adding a 2nd if you so wish.

Don't use Crossfire. Buy a single card with twice the performance whereever possible, there are numerous disadvantages of CF (power consumption, microstuttering, CF drivers not scaling with new/obscure games, and poor scaling in most cases anyway (only about +50% instead of +100% theoretically for a second card).

A 5850 would be a huge jump from a 4850 and allow you to turn all the settings right up even on high resolutions.

(Also, nothing you can reasonably do can improve GTAIV, just give up on that.)

NEVER!!!!!   .........    ...... ;(

Well i initially wanted to only upgrademy 4850 to another single card but the thing is that a 5850 card costs like >500$ for me in Poland and a 5870 is more like >700$ so you understand why i thought of using crossfire with two 5770 which would cost  about 450$ :/.

Sadly, Crossfire probably just won't work. The technology involves having two different video cards alternate rendering frames, except getting two video cards to communicate with that level of precision creates a whole host of problems, mostly related to microstuttering. Microstuttering can actually cause a 60 FPS game to play like a 30 FPS game, complete with increased input lag, so there's really no point to it; it's just a higher framerate without any of the benefits of a higher framerate.

If you really want to max out games at any common resolution lower than 2560x1600, a single 5850 will do you just fine.

And don't worry about Crysis 2. Even today, the first Crysis brings even a 5970 to its knees at max settings/AA/resolution. And that game was released in 2007. I don't expect that anything lower than a 5850 will even be able to run Crysis 2 at playable framerates on high settings.

I didn't want to shop online. It becomes a pain in the ass if the card doesn't work properly. Also the 4850 requires a superior power supply than what I have.

The 360 is my primary gaming machine. I just use the PC for a few games.

In that case you could import them? But in any case the two 5770s may be a better choice at those prices!

The Radeon 4850 actually consumes slightly less power than some 9800 GT models at both idle and load. Check out this chart for a comparison (scroll down a bit).

Any PSU that can handle a 9800 GT can handle a 4850.