LATEST UPDATE (August 11, 2012): The XPS 8300 now supports OS X Mountain Lion. According to this post, the standard Unibeast method of updating works fine.
Dell XPS 8300 ($1600+)
Sandy Bridge generation. You can choose between an i5 or i7 processor, both of which are more than enough for everyday usage. Like most prebuilt computers, the XPS 8300 comes in a relatively small mid-tower case. This makes it more portable, but also makes it a pain to upgrade with new parts.
Beyond the processor, the XPS 8300 includes a DVD/Bluray drive, 6 to 16 GB of RAM, and a 7200 RPM hard drive. Some models of the XPS 8300 also have a WiFi adapter and a sound card. What graphics card you get with the XPS 8300 depends on which model you purchase (more on this in the next section).
There are multiple models of the Dell XPS 8300 spanning over a large price range, from a bargain-bin price of around $500, to over $2000 for the most expensive models. Unfortunately, the only models that can be turned into Hackintoshes are the expensive ones. The cheapest models use integrated Intel HD 2000 graphics, which don't really work with Mac OS X. Instead, you'll have to purchase a model with a compatible graphics card, such as the Radeon HD 6870 (the Radeon HD 6870 model of the XPS 8300 costs around $1800-2000). Mid-end models of the XPS 8300 use the Radeon HD 6450, which does not seem to work with Mac OS X either. If necessary, you can simply purchase a compatible graphics card from a computer parts retailer, and install that card inside the XPS 8300 yourself.
Hackintosh Compatibility: Impressively, almost everything on the XPS 8300 works with Mac OS X Lion. This includes booting from the hard drive, ethernet, sound, and graphics (assuming you bought the right model). You can update Lion without a problem. The main thing that doesn't work is sleep mode, because there is no DSDT file available for the XPS 8300.
Otherwise, the only incompatible parts of the XPS 8300 are the peripherals. The WiFi adapter included in some models (the Dell 1501 Wireless-N card) doesn't work, so you will have to purchase a separate WiFi adapter. The sound card included in certain models is not likely to work, either.
Thanks to the efforts of Gravewyrm from tonymacx86, the Mac OS X installation process for the XPS 8300 is very well documented; we've provided a link to Gravewyrm's guide at the bottom of the article. The standard Unibeast installation method for Mac OS X Lion works on the XPS 8300 without the need for too many extra tweaks. It is likely that the iAtkos installation method for Lion would work as well, if that's your preference. The XPS 8300 hasn't been tested with Mac OS X Snow Leopard, but you can probably install Snow Leopard on the XPS 8300 with the standard iBoot method.
Once you've installed Mac OS X Lion with Unibeast, it's just a simple matter of running Multibeast, and installing two extra kext files to enable ethernet (provided in Gravewyrm's guide below-- you must register on tonymacx86 to view the files). Be sure to follow Gravewyrm's instructions closely on this step. When you're done, you'll have yourself an almost fully-functional Hackintosh, that you didn't even have to build. Congratulations!
Resources: [SUCCESS] Project "iDell" XPS 8300 *Lion 10.7.3*