Desktop Apps

Platforms
Windows, Linux and Mac OS
Languages
C, C++, VC++, C#, Java, Objective C
Scripting Languages
Perl, Python, Shell Scripting, PHP
Methodologies
OOP, UML

Mobile and Tablet

Platforms
Android, iOS
Languages
Java, Objective C
Others
GUI Frameworks for Mobiles, Android NDK, JNI Development

Middleware

COM, ATL, Direct X, Socket programming, Device drivers

Embedded Applications

Embedded Multimedia
ARM, Intel, Renasas, Microchip
Embedded Protocol Stacks
USB stack, TCP/IP stack, Bluetooth and BLE

Firmware and Drivers

Processors
ARM, Intel, Renasas, Microchip
RTOS
QNX, FreeRTOS, RT Linux, Android, Windows Embedded
Bootloaders
U-Boot, Grub and other custom bootloaders for various processors

BSP development involving various peripherals like NAND flash, SDRAM and other devices.

Hardware Development

CAD Tools:
OrCAD, Eagle CAD, Altium Designer
Hardware Tools:
Oscilloscopes, Multimeters, Logic Analyzer, Signal Generators