With computer components being integrated, systems are getting smaller, yet the performance is getting better. Both Intel and AMD integrated memory controllers onto the CPU die, and the latest Intel Sandy Bridge comes with native on-die integrated graphics. The need for a large system with various chips is no longer needed--small and integrated is definitely the trend.
Intel spearheaded the Atom platform where a very small processor is powerful enough compare to a desktop processor from 3-4 years ago, yet consumes only a fraction of the power. AMD's latest Zacate APU is their answer to the Intel Atom platform. Like the Atom processor, the Zacate APU is designed for low power consumption with decent performance. The Zotac ZBOX retails for $339.99 on Newegg.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips