How much would the top bit coin mining rig cost. Around 2,000$? Looking for a rig that would be extremely well. Any help or information is highly appreciated.
Short answer to your question: a mining rig could cost just about as much as you wanted it to.. You could build a rig with 4 6990's and lots of other expensive hardware to go with it that could easily cost over 2,000 USD.
If you are looking for advice, it sounds like you are looking for a rig with the best MHs/$, I would suggest you look at this page
https://en.bitcoin.it/wiki/Mining_hardware_comparison which has a comprehensive list of most GPUs and their MH/s, power consumption in Watts, and other useful information like what miners and parameters people are using to get the results they posted.
Be careful not to pay too much attention to things such as the price of the cards listed on that site, as those prices tend to have changed a lot.
I would recommend buying an AMD A8 based rig, which offers about 50 MH/s from the APU's built-in GPU alone; then start with a good mobo, like this one here
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157257 -You'll need a large case, full tower ATX to fit a double slot GPU in the last slot though.
Then start by adding some GPUs with a good MHs/$/KWh; I would recommend the HD 6770 to go with the board I recommended; it looks like people were able to achieve about 240 MHs with that card, and at $110, thats a little over 2 MHs/$; Assuming they consume no more than 110 Watts when overclocked (I have a 6870 that consumes about 110 watts when clocked at 1000MHz), that's a pretty good power consumption ratio as well.
Ideally you'll want a power supply that at least 80-plus Bronze certified, and can output at least 150 watts more than your maximum power consumption is going to be; a rig with an A8 and 3x 6770s would probably run around 550 watts max, maybe as low as 475-500 if you down-clock the memory and use a solid-state drive, so you'll be wanting a PSU with about 650-750 watts.
RAM and other stuff such as that matter much less unless you are planning on using the rig for gaming on the side.
