Every year, a wave of nostalgia comes crashing down as we make the final tweaks and finishing touches to our annual Dream Machine. Because we remember the amazing machines we built in the past, and know that the knowledge we gained and the lessons we learned directly influence our newest ultra-beast computers, year after year. So, as we wipe the sweat from our brows for 2010, we invite you to take a look back at four awesome Dream Machines of the past couple of years. Click to enlarge if you'd like to pick up some spiffy new wallpapers. Enjoy!