First time builder, AMD light gaming build, $700 budget

[brewtown]

Hi all, and thanks for this great forum and all the help you dispense to folks like me. This will be my first build. I have been reading this forum for about a month to educate myself and I think I'm close to having a good system specced out. I have a couple of questions and would also appreciate it if someone could verify that I've selected compatible components. I am fairly confident that my homework has paid off, but I'm new to this and could be overlooking something obvious.

I am building a system for my home and the main uses will be basic office productivity, web, and light gaming such as Lord of the Rings. I'm not looking for a hardcore gaming rig, but I would like to be able to run LOTRO with all graphics settings at high. There is also the potential that I could be loading a statistics package or GIS software (similar to CAD if not familiar) at some point, and I would like something that has the legs to upgrade over the next 3-5 years if possible. My budget is set at around $700, including operating system and I already have a monitor and all peripherals. I'll be purchasing the components between now and the end of the month, watching for sales and free shipping on Newegg.

My proposed build:
Case: Antec Three Hundred Black Steel ATX Mid Tower Computer Case - Retail: http://www.newegg.com/Product/Produc...82E16811129042

PSU: Antec EarthWatts EA650 650W Continuous Power ATX12V Ver.2.2 / EPS12V version 2.91 SLI Certified CrossFire Ready 80 PLUS: http://www.newegg.com/Product/Produc...82E16817371015
Price for case and psu combo: $110

CPU: AMD Athlon II X4 620 Propus 2.6GHz 4 x 512KB L2 Cache Socket AM3 95W Quad-Core Processor - Retail: http://www.newegg.com/Product/Produc...82E16819103706
Price: $100

Mobo: ASUS M4A79XTD EVO AM3 AMD 790X ATX AMD Motherboard - Retail: http://www.newegg.com/Product/Produc...82E16813131402
Price: $105 (plus a $10 rebate)

or: GIGABYTE GA-MA790GPT-UD3H AM3 AMD 790GX HDMI ATX AMD Motherboard – Retail: http://www.newegg.com/Product/Produc...82E16813128398
Price: $115 (plus a $15 rebate)

HDD: Western Digital Caviar Black WD6401AALS 640GB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive: http://www.newegg.com/Product/Produc...82E16822136319
Price: $75

RAM: G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model F3-12800CL9D-4GBNQ – Retail: http://www.newegg.com/Product/Produc...82E16820231193
Price: $95

Video Card: ASUS EAH5750/2DIS/1GD5 Radeon HD 5750 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail: http://www.newegg.com/Product/Produc...82E16814121351
Price: $145

Pri Optical: LITE-ON 24X DVD+R SATA Black 24X DVD Writer LightScribe Support - Retail: http://www.newegg.com/Product/Produc...82E16827106335
Price: $35

OS: Microsoft Windows 7 Home Premium 64-bit for System Builders - OEM: http://www.newegg.com/Product/Produc...82E16827106335
Price: $110

Total Price without rebates, if I go with the Asus mobo and graphics card: $775. That puts me over where and I want to be, but there are some other combo deals I could use to lower the price and I'd expect more sales as we approach black Friday.

My questions:
1. Am I correct in thinking that the Athlon II will serve me better than the Phenom, since I am not planning on any hardcore gaming?

2. Are there any major differences between the mobos other than the onboard graphics on the Gigabyte? My thinking is I will go with the Asus if I can afford a video card right away and go with the Gigabyte if I'm surpassing my budget and add a video card later. Good logic or have any other suggestions for a mobo?

3. I'm a little overwhelmed with the RAM choices. Will the one I selected work and is there something else you'd recommend at a similar price?

4. I'm likewise a bit in the dark with graphics cards. The ATI 5750 seems like it will do all I could possible want at a great price, but the competing brands are confusing. I also looked at Sapphire, but choose the Asus to match the mobo. Is that important and is there a different manufacturer I should be considering?

5. Any other suggestions that would improve my build while staying around $700?