Hi Vead,
Here under few considerations about.
The main decision elements are:
software side
Atmel offer a free programming environment, AVRSTUDIO and a free C compiler.This set is compatible with all they 8 bits uC familly.
http://www.atmel.com/microsite/avr_s...ource=redirect
Microchip offer free programming environment, MPLAB with a free limited C compiler. This set is family depending, each familly as is own compiler.
http://www.microchip.com/stellent/id...&redirects=c30
Independent compiler are also available, here a range of C, Pascal and Basic compiler for both Atmel and Microchip.
http://www.mikroe.com/
Here a basic compiler for Atmel (2K code size version is free)
http://www.mcselec.com/
Here a basic compiler for Microchip
http://melabs.com/
hardware side
Olimex made boards for both. They have a wide range of good value for money products.
http://www.olimex.com/dev/index.html available at Mouser and Farnell
Futurlec also have few good value for money products.
http://www.futurlec.com/DevelopmentBoards.shtml
and
http://www.mikroe.com/ again.
Programming tools
both brand offer cheap in situ programming pods and many clones are available on ebay, exemples:
http://www.ebay.com/itm/NEW-Mini-ATM...item336dda15b8
http://www.ebay.com/itm/Clone-Microc...item5199254cfd
Popular products
Arduino is a very popular open source of project based on Atmel product. He combine a programming environment and very flexible harware platform. just google it.
PICAXE is a popular commercial product based on Microchip uC. It use Basic language in place of C what can make a shorter learning curve. The Basic is included in the chip itself. The code is interpreded not compiled so. Mean that you must bought a new PICAXE chip for each project, not a blank standard one.
http://www.picaxe.com/
Componants
Both brand can offer you almost any componants they will fit your needs. A good choice to start is a uC including all standards peripheral (ADC, PWM...) and an uart to ease the debugging (and programming if you use a bootloader).
You can narrow down your choise with the ATMEGA8 or 88 for Atmel and PIC16F876 for Microchip.
Another thinks to take into account it's the guidance and the tools you can find around you.
Olivier