The Pandora is a powerful open source linux based gaming machine that is going to be available in the UK for £199.99 by the end of September. According to the developers of Pandora, it is going to be the most powerful handheld in the world both in terms of raw CPU power and 3D graphics capability. Judging from the specifications I personally think that it is going to be the most powerful handheld device available today. Read more about it here

Specifications:

CPU:ARM® Cortex™-A8 600Mhz+ CPU running Linux
430-MHz TMS320C64x+™ DSP Core
Video: PowerVR SGX OpenGL 2.0 ES compliant 3D hardware
Display: 800x480 4.3" 16.7 million colours touchscreen LCD
Connectivity: Wifi 802.11b/g, Bluetooth & High Speed USB 2.0 Host
Multmedia: Dual SDHC card slots & SVideo TV output
Gaming:Dual Analogue and Digital gaming controls
Navigation:43 button QWERTY and numeric keypad
Battery: Around 10+ Hours battery life

Source: Tech Radar