Just what I need. Now that we've made a mongo (12 gallon tank) monster PC that is running at an amazing 150fps on Black Ops II and 1GBps disk access on an overclocked 4.5GHz Ivy Bridget 3570K processor and dual GTX670 SLI overclocked by 72Mhz and 200MHz on memory, time now to look at smaller machines. Things that are lunch pail sized for both budget and also as an ultimate gamer machine.
Looking at both Anandtech and SilentPCReview, here is what I came up with to build a very fast overclocked system that is alos quiet. It is designed to be a very fast desktop system where you are mainly doing photo editing and video but not gaming. Should last a long time with an overclocked system and a big cooler. Perfect for putting into mineral oil as it uses the mini ITX form factor:

1. CPU. Intel 3570K. $215. It is expensive, but it is unlocked so easily overclock to 4.5GHz from its normal 3.4GHz and it is quad core. 2. Ram. The Samsung DDR3-1600 8GB is just$35 but is very overclockable.
3. Motherboard. ASUS P8Z77-I Deluxe at $180 (or the Asrock seems less reliable but is just$150).
4. GPU. The dedicated H4000 should drive most oridinary uses pretty well and saves lots of dolalrs
5. SSD. Going to a $110 SSD means much higher performance. Windows should boot in half the time and defragmentation won't happen. The OCZ Vertex 4 128GB or the Mushkin Chronos Enhanged 120GB are both$110.
6. Case. Silverstone SG05 is recommended by SilentPCREview. it has a built in 300 watt small power supply and unlike the Apex Mi-008 recommended by Anandtech has a  78 mm clearnace for the cooler rather than 40mm. Tje ;atest model is the SG05BB now with a 450 watt supply at $110. If you slightly larger, the SG07 is about 3 inches longer and has a huge 600 watt power supply and has a lot more fan clearance at 117mm with a big 180mm fan above it so it might even work passively cooled but does cost$180.
7. PSU. This is included in the case price and 300 watts should be OK.
8. Cooler. Expensive but the noctua nh-l12 with the nexus 120 mm fan is super efficient but blocks the pcie slot. It his is ok for this build but if you want to use pcie then you'll need a taller case to accommodate a vertical tower like the noshiua dh-14 for instance which can fit if the PCI graphics card isn't too big and you get a larger case.

If you wanted to build an amazing gamer PC in this tiny form factor, then the build is about the same but you would use a bigger box:

1. CPU.Intel 3570K. As above
2. Ram. Samsung DDR3-1600 8GB as above.
3. Mobo. ASUS P8Z77-I Deluxe.
4. GPU. GTX-690. Investigate if this will fit and which OEM to use.
5. SSD. Need a little more space for games, perhaps the Samsung 840 (if the firmware issues are resolved).
6. Case. Silverstone SG07. \$180.
7. PSU. Included 600 watt supply
8. Cooler. See if the DH-14 can fit, depends mainly on the size of the 690GTX

Here were the resources I used:
AnandTech - Small Form Factor Buyer's Guide

In this guide we've outlined small form factor gaming desktops, a file server, and on the next page, a diminutive desktop that won't break the bank.