I am going to build my new PC. My major focus of activities will be - usual office applications, 2D-3D graphics designing, adobe applications, simulation applications (MATLab/MathCad), creating flash animation, video editing, simple video making, learning sound editing applications, watching HD movie, little bit of gaming etc.
Cooler Master RC-692-KKN2 CM690 II Advanced ATX Mid-Tower Case - ATX, 7+1 Expansion Slots, USB 2.0, Front blue LED fan w/ SSD adapter & built-in hard drive dock. "Awarded 10/10 by lanoc.org" (C283-2064)
You can get away with just four gigs of ram to get you started. I think that you can find a better deal on a monitor, I just picked up a 23" for about $139.00 If you get this gigabyte board it has built in 7.1 surround sound. The board also has a pretty good integrated video card with both VGA and DVI connections if you just want to get it built and save some money.
^+1 on the sound card stuff.
I think 8gb of RAM is justified if you're doing media work. It's only $20 or $30 more. I recommend Ripjaws - cheap and reliable.
Also, I think the case that iwillfix suggested is too expensive. You can save another few dollars there, making about $30 extra after eating the price of the extra RAM with the sound card money.
It's gotta be a 2500K, not a 2500. Free performance.