Desktops forum: which one should i invest in???

Even though price isn't an issue for you, I wouldn't pay a premium for a top of the line CPU. Today, a Core 2 Duo should be fine for what you do. Since you watch movies, maybe put the extra cash towards a nice monitor or a killer surround sound system.

I'm currently running a Core 2 Duo, and it's incredibly fast. I would say that a quad core isn't really necessary. I agree with the other people, perhaps a lot of money shouldn't be invested in the computer itself, but with other features like a nice monitor and speakers. For a monitor I would suggest a Dell 24" or potentially a 30" if you are willing to spend the cash. A Logitech 5.1 surround system like the 5450 would do you very well. A good sound card (X Fi of some type) and a decent graphics card would serve you well, I don't know how many games you play. If you don't game much, I would suggest a 7600GT. I would also stay away from the Core 2 Exteme X6800, because for about the same price you can get the quad core Core 2. For your needs though I think a Core 2 Duo e6700 would probably be best. For movies and entertainment a good sound card/monitors/speakers is always a good deal. Also, a very nice new TV Tuner came out - the Vista View Saber, which if you have an available PCI-e x1 slot it is available (cnet review here: http://reviews.cnet.com/Vista_View_Saber_2020/4505-8902_7-32166004.html). Investing in Windows Vista Home Premium or Ultimate when it comes out is highly recommended too. Unless money really isn't an issue at all, I would go dual core. But if your heart is set on quad core, I would go with the Intel QX6700, with the above components as well.

ya c2d e6700, 7900 gtx, 2gb ram, a nice MB wud be fine for that

the 7900 gtx has hd dvd capability wich he might want with such a good monitor

I wouldn't worry about getting a quad-core system but rather focus on having a big network connection where you may connect over some fiber-optic connection if you want "lightning fast" downloads as with the downloads and the IMs and the surfing these all share the same pipe which is the connection you'd have and you did say that price wasn't a factor. I'd suspect most AMD Athlon 64 x2s or Core 2 Duos wouldn't break a sweat on these things and if you have at least a couple gigabytes of RAM then you should be fine except for that network connection.

Regards,
JB

I use a 500mhz, 160MB of Ram, 2x20 gb hard drives to download all my 'legal isos of linux distros'. I even run peer guardian 2 in the background.

im planning on having a Panasonic TH-37PH9UK double as a tv monitor as well as a comp monitor, a ps3 for gaming as well as playing blue-ray movies, and the computer is the last thing i have to decide on. sound is my last priority. but if i have the cash, ill go for good sound as well. si o no in terms of the setup???

I can't believe no one mentioned RAM.
Having an adequate amount of memory is possibly the most important factor in doing all of those things at once with no slow down. (Obviously, connection speed is very important, and a good processor too)

Basically, all the stuff your computer is currently doing is stored in the RAM. If it runs out of RAM, it starts using the Hard Disk to store data. One analogy is that the RAM is your desk and the Hard Disk is a file cabinet down the hall. Imagine having to make a few hundred trips up the hall every day because your desk is too small.

The above recomendations are good (like a quality video card for actually *viewing* the movies) but for the tasks you described, make sure to get 4Gb of RAM (2Gb, if cost is a concern; but not less, or expect slowdowns)