CPU: i5 750. Like there are any other choices.
MOBO: Depends. If you won't upgrade the mobo, your best bet is the get the latest tech available. That'd be USB 3.0 & SATA III. No, there aren't any parts that take full advantage of them, but there WILL be. So back to the question of how often you upgrade. These are good starts:
http://www.newegg.com/Product/ProductList.aspx?Submit=E...
RAM: This seems like a very popular item around here, and I wouldn't hesitate to get one:
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL8D-4GBRM - Retail
* Free Shipping
* Your Price:$91.99
Now again, how often do you upgrade? If you can afford it right now and won't upgrade ram, you might want 8GB. Just one more ram ripjaws kit. That'd be 4 x 2GB. 2 x 4GB is not worth the money. $400+. Any modern ATX mobo will have 4 slots for memory. More ram will speed up video/photo editing and multitasking. Regardless, if you can, get Windows 7 64bit.
GPU: LOTRO sys. req. are kind of low. You should aim to meet or exceed the RECOMMENDED.
http://www.lotro.com/component/content/article/369-syst...
The HD 4870 is a good choice. If the HD 4890 isn't too much more expensive, get that. However, they and along with most cards are last generation. If you're getting Windows 7, get the HD 5770 for about the same price.
NOISE: There are many things you can do to cut down the noise from a pc. Like turning on Speedstep or Enhanced Intel® Speedstep Technology. It will slow down the cpu when idle. Then your cpu fan will throttle down as well.
http://ark.intel.com/Product.aspx?id=42915
Also, you can buy a fan speed controller for $20 that controls 4+ fans in the case. Turn the knobs to the middle when you're working and max 'em out when you're gaming. Or even daisy-chain the fans to one knob.
Most important would be the case. Look at Antec mid to full tower cases with doors. They're very quiet. Some of them have sound-proofing. Like the Sonata with PSU:
Antec Sonata III 500 Black 0.8mm cold rolled steel ATX Mid Tower Computer Case 500W Power Supply - Retail $109.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Yes, it's sufficient for HD 4870/90 & 5770.
http://www.amd.com/us/products/desktop/graphics/ati-rad...
http://www.amd.com/us/products/desktop/graphics/ati-rad...
http://www.amd.com/us/products/desktop/graphics/ati-rad...
Q's: How does the camcorder connect to PC? Firewire/USB? Also, the digital camera if any.