Last time I went parts shopping for a new build, I went to newegg and started looking at cases with a bazillion reviews. Some really inexpensive cases have over 5000 positive reviews, so you may be pretty safe. I ended up with a (now discontinued) coolermaster mini-tower for about $45, and it has been awesome to work with. Newegg sells a few hundred different kinds of cases so go to their case pages, filter by whatever features you need (mobo size, with or without PSU, USB 3.0 ports, whatever you need/want), and then sort by price. Work from the lowest price up to the first case that has a few hundred or more reviews and has the looks/features you want. That's where you START
Then google that case and look for any review sites that looked at the case.
It doesn't really take all that long.
You need:
Case - big enough for your parts including motherboard size
PSU (power supply), probably need minimum 450-500w for a reasonably priced build
Motherboard - needs to support the latest consumer intel cpus. your choice will revolve around brand, size (atx, mini-atx, etc), and how much money you want to throw at extra features.
CPU - I strongly prefer intel for performance and reliability, plus better driver support. Get the fastest quad core intel i5 cpu that fits your budget.
Memory - absolute minimum 4GB for win7, 8GB is a sweet spot right now, 16GB will mean you can pretty much forget about upgrading memory because you'll have "enough" for a long time.
hard drive - Depends 100% on how much money you have to throw at speed. $150ish will get you a very nice/fast 2GB western digital black. $400ish will get you a 1TB Samsung 840 EVO SSD which is super fast and should be very reliable. I strongly recommend against getting a small "boot drive" SSD, because you'll end up having to fiddle with it all the time. If you absolutely must have an SSD and can't afford a big one, get at least a 256GB SSD, match it with a 1 or 2 TB regular hard drive, and move your "personal folders" to the bigger drive. I personally saved my pennies and got 1TB SSDs and a big external network shared storage device for really big stuff, so I wouldn't have to fiddle with it.
Video card. You pay for speed, period. I prefer NVidia but that's my personal preference. Shop around.
Optical drive - DVD-RW for cheap, or BD drive if you want to watch Blu-ray movies on your pc
Keyboard/mouse
Monitor - TN panels are faster for gaming, but their colors suck and the color changes when you move your head. PVA and IPS panels have better colors but might streak or smear a bit with very fast action on the screen. IPS panels sometimes have bright "black levels" so they're not always the best for watching movies on the computer, but a premium IPS panel will have the best color gamut and accuracy after calibration. You can get a decent cheapo IPS panel 22-24" in size for well under $200 on sale. That kind of monitor wouldn't satisfy a professional photographer but its plenty good enough for most uses. Look at gaming websites for recommendations for gaming monitors.
For PSU, you can do the sort/filter thing or just take someone's advice. I love seasonic power supplies. Slightly more expensive but all 4 of my seasonic PSUs have been running for years without any problems and they're very quiet.
For mobo, I go with a name brand and again filter by features, sort by price, and work from the bottom up until I get the cheapest one with the right features. I have had the most good luck with ASUS motherboards over the last 15 years, hands down.
Memory, I like g-skill but the key is to not over-buy speed. Get memory rated for the max "non-overclocked" speed of your mobo and cpu and you'll be fine. 8GB is the sweet spot for now I think.
Hard drive - again, I like a 1TB SSD. I have 2 Samsung 840 EVO drives and they're fast. Early reports questioned their reliability due to the technology used but so far there have been ZERO reports of any sort of inherent flaw in these drives, after a couple of years on the market.
CPU - get the fastest quad-core intel i5 cpu you can afford. You don't need an i7 cpu for gaming unless you also run multiple virtual machines (like you're running multiple game servers or just want multiple VMs for some reason), and the i3 cpus are cut down too much for gaming in my opinion. Don't get "Pentium" or "Celeron" branded cpus as they're really cut down, unless you are truly on a miniscule budget.
As for wholesale prices, you'll have to shop around, really. You can find deals at amazon.com or any number of smaller shops, but I've found that the good return policies of amazon and newegg pretty much balance out any price difference, and amazon prime free shipping can make a huge difference in final cost when buying lots of components.
