If you are interested in doing development on a BeagleBoard, BeagleBone, or a Raspberry Pi, you might find the following feature comparison table useful.

Price
Raspberry Pi (Model A) $25
Raspberry Pi (Model B) $35
BeagleBoard $125
BeagleBoard xM $150
BeagleBone $89
BeagleBone Black $45
SoC
Raspberry Pi (Model A) BCM2835
Raspberry Pi (Model B)
BeagleBoard Texas Instruments OMAP3530
BeagleBoard xM Texas Instruments DM3730
BeagleBone Texas Instruments AM3358
BeagleBone Black Texas Instruments Sitara AM335x
CPU**
Raspberry Pi (Model A) 700 MHz ARM11 (core of SoC)
Raspberry Pi (Model B)
BeagleBoard 720 MHz ARM Cortex-A8 (core of SoC)
BeagleBoard xM 1 GHz ARM Cortex-A8 (core of SoC)
BeagleBone 500 MHz-USB Powered, 720MHz-DC Powered ARM Cortex-A8 (core of SoC)
BeagleBone Black 1 GHz ARM Cortex-A8 (core of SoC)
GPU
Raspberry Pi (Model A) Broadcom VideoCore IV (core of SoC), supports OpenGL ES 2.0, OpenVG 1080p30 H.264 high-profile encode/decode
Raspberry Pi (Model B)
BeagleBoard Imagination Technologies PowerVR SGX530 GPU (Core of SoC)
BeagleBoard xM
BeagleBone
BeagleBone Black
DSP
Raspberry Pi (Model A) Core of SoC, but without public API
Raspberry Pi (Model B)
BeagleBoard TMS320C64x+ (core of SoC, 520 MHz up to 720p @30 fps)
BeagleBoard xM
BeagleBone None
BeagleBone Black
Memory
Raspberry Pi (Model A) 256 MB SDRAM (shared with GPU)
Raspberry Pi (Model B)
BeagleBoard 512MB SDRAM (shared with GPU)
BeagleBoard xM 512MB MDDR SDRAM
BeagleBone 32KB EEPROM, 256MB DDR2
BeagleBone Black 32KB EEPROM, 512MB DDR3L
USB
Raspberry Pi (Model A) 1x USB 2.0 Host Port
Raspberry Pi (Model B) 2 Port USB 2.0 Host Hub
BeagleBoard USB HS Host Port, HS USB 2.0 OTG Port
BeagleBoard xM 4 Port LS/FS/HS USB Hub, HS USB 2.0 OTG Port
BeagleBone HS USB 2.0 Client Port, LS/FS/HS USB 2.0 Host Port
BeagleBone Black
Video Outputs
Raspberry Pi (Model A) Composite Video, Composite RCA, HDMI
Raspberry Pi (Model B)
BeagleBoard DVI-D (via HDMI port), S-Video
BeagleBoard xM
BeagleBone None
BeagleBone Black HDMI
Audio Input
Raspberry Pi (Model A) None
Raspberry Pi (Model B)
BeagleBoard 3.5 mm stereo jack
BeagleBoard xM
BeagleBone None
BeagleBone Black
Audio Output
Raspberry Pi (Model A) TRS connector, 3.5 mm jack, HDMI
Raspberry Pi (Model B)
BeagleBoard 3.5 mm stereo jack
BeagleBoard xM
BeagleBone None
BeagleBone Black Stereo via HDMI
Onboard Storage
Raspberry Pi (Model A) Secure Digital, SD / MMC/ SDIO card slot
Raspberry Pi (Model B)
BeagleBoard 6 in 1 SD/MMC/SDIO 4/8 bit support, dual voltage card slot
BeagleBoard xM microSD
BeagleBone
BeagleBone Black 2GB eMMC, microSD
Onboard Network
Raspberry Pi (Model A) None
Raspberry Pi (Model B) 10/100 wired Ethernet RJ45
BeagleBoard None
BeagleBoard xM 10/100 SMSC LAN9514 Ethernet HUB
BeagleBone 10/100 SMSC LAN8710A
BeagleBone Black
Supported Interfaces
Raspberry Pi (Model A) SPI, I2C, I2S, UART, JTAG
Raspberry Pi (Model B)
BeagleBoard McBSP, DSS, I2C, UART, McSPI, PWM, JTAG
BeagleBoard xM McBSP, DSS, I2C, UART, McSPI, PWM, JTAG, Camera
BeagleBone 4x UART, 8x PWM, LCD, GPMC, MMC1, SPI, I2C, A/D Converter, 2xCAN Bus, 4 Timers, FDDI USB to Serial, JTAG via USB
BeagleBone Black 4x UART, 8x PWM, LCD, GPMC, MMC1, 2x SPI, 2x I2C, A/D Converter, 2x CAN Bus, 4 Timers, FDDI USB to Serial, JTAG via USB
GPIO Header
Raspberry Pi (Model A) 26 pin expansion header (8x GPIO)
Raspberry Pi (Model B)
BeagleBoard 28 pins (multiplexed)
BeagleBoard xM
BeagleBone 66 pins
BeagleBone Black 2x 46 pins
Real-time Clock
Raspberry Pi (Model A) None
Raspberry Pi (Model B)
BeagleBoard Optional
BeagleBoard xM
BeagleBone None
BeagleBone Black Yes
Power Source
Raspberry Pi (Model A) 5V via Micro USB or GPIO header
Raspberry Pi (Model B)
BeagleBoard 5v via OTG USB, GPIO header, DC power jack
BeagleBoard xM
BeagleBone 5v via USB, DC power jack
BeagleBone Black 5v via USB, DC power jack, or expansion header

** ARM conservatively estimates that the Cortex-A8 is capable of executing 40% more instruction per second than the ARM11 given equal clock speeds. Additionally, multimedia processing on the Cortex-A8 will outperform the ARM11 by a factor of two due to the NEON extended instruction set. These advantages combined with Cortex-A8′s significantly faster memory cache result in a relative performance differential that is difficult to evaluate when looking at clock speed alone.

http://www.anandtech.com/show/2798/5