I've never built a system before so looking for some suggestions on what I can get for around $800. The system will be running ubuntu only and will be used primarily for development. I will have two monitors so maybe I need a graphics card with dual dvi? Also since speed is really important I'd like to get an SSD if it fits into my budget.
Approximate Purchase Date: within the next two weeks
Budget Range: $800
System Usage from Most to Least Important: Development, movies
Are you buying a monitor: No
Parts to Upgrade: N/A (new build)
Do you need to buy OS: No (I will be installing ubuntu 12.10)
Preferred Website(s) for Parts: newegg
Location: City, State/Region, Country - Boston, MA, USA
Parts Preferences: NA
SLI or Crossfire: No
Your Monitor Resolution: 1920 x 1080 ( I will be adding a second monitor at some stage)
Since you're not gaming and you care about speed at under $800, you'd probably do best with an AMD system. AMDs do very well on Linux (equal to or better than Intels at a much lower price point) except on some very specific scientific computing applications: http://www.phoronix.com/scan.php?page=article&item=amd_...
If you don't need 8 cores, the 5800K does very well. If you do, the 8350 is top of the line, but the 8150 still does very well for non-gaming purposes. The difference is a substantial chunk of your budget, so you'll need to decide what you need.
My experience, and I think a lot of people more-or-less agree, is that Nvidia cards work better with Linux. I just think their (proprietary) drivers are better. You don't need anything crazy, but a modern GTX card is probably going to make your Ubuntu experience nicer. They've been out long enough now that they seem to have the kinks worked out. The 650Ti I'm suggesting is a nice low-midgrade card with dual DVI that would be adequate for casual gaming and more than adequate for anything else (uness you intend to do GPU computing, but then I'd expect to see a bigger budget).
The motherboard I'm going to recommend is slightly more expensive than you really need, but it has good support for Piledriver if you want the 8350, a great BIOS, and nice overclocking utilities. The difference between it and the cheaper models isn't huge.
I'm suggesting a 256GB SSD, but if you need to store large amounts of data, maybe go for the 128GB of the same model and spend the rest on HDD storage. I find I don't fill up my Linux boot very quickly myself, but your mileage may vary depending on what you're developing.
Case is up to you, but I think the 300R is amazing for the price. (Don't do the 200R, it's not up to Corsair's usual quality standards. But the 300R is solid midgrade quality - they just cut the bells and whistles from their midgrade cases.)
Aftermarket coolers are highly recommended, and essentially required for overclocking. The Evo and Plus are some of the best-known budget coolers, but others will do the job. Note that the Plus won't work on the Socket FM2 board.