Microcontroller newbie needs some advice re. PICs and AVRs.

[WarSim]

Stating things as if they are unique to AVR when they are not is a bit silly.  So I am going to assume you are saying you like the way AVR implements these common features. 

AVR has I/O pins that allow electrical energy flow in and out of the chip! 
AVR has power pins! 
AVR has full software simulation!
AVR has hardware snoop!
AVR has a debug interaction mode! 

Both chips and IDEs are very feature similar.  There are differences in the naming conventions, two name for the same thing. 

[nctnico]

@elcomtel:
You better investigate for yourself whether ARM controllers are really more difficult than PIC / AVR or that its just people parrotting other people.

[dannyf]

whether ARM controllers are really more difficult than PIC / AVR

Agreed. The newer chips are just more powerful and with more advanced peripherals. Other than that, not much difference.

[Rellum]

My 2 cents

Don't underestimate Arduino , it has good points, don't care about the critics, you can learn a lot with it. I learned (and quickly than PIC/AVR alone) ! And remember you can always build your own version, it's open source.

Try Both AVR and PIC solutions, pick whatever you find most suitable for you or use both. MPLAB X is good as AVR Studio is. Both are not "the best" but they are "the best free available" and for start to play around that's quite enough.
Start small and scale after. As you are quite proficiency you won't take too much time to learn the basics. As you are also from old school, a book is always welcomed. I liked a lot Designing Embedded Systems With Pic Microcontroller. It uses a 16F84 which maybe not the best choice by now but which will guide very well.

Regarding ARM, my opinion is forget it by now. Start simple, build your projects, and then go ARM. Don't go straight to ARM, nobody deserves this !

[westfw]

In the microcontroller "software development" world, "JTAG support" most often seems to refer to "using JTAG protocols to access internal registers that control the debug capabilities of the chip", rather than the more traditional "provide ability to set pin states to arbitrary values for system-level debugging."  (huh.  I don't even know whether JTAG on AVR offer pin-setting.  Atmel doesn't seem to document much of their debug capability.)

The other implementation of emulation (I suspect this is the case with JTAG enabled microcontrollers) is to have the microcontroller 'twiddling its thumbs' doing nothing while the host takes full control of all the pins via JTAG under the control of a microcontroller simulator running on the host. This way you can make the 'physical' microcontroller appear to be running the show, where in fact the signal stimulus is done by JTAG.

That seems EXTREMELY unlikey.  The whole point of having on-chip debugging aids is to permit the code to run at full-speed, except when debug functions are explicitly invoked.  There are tools like AVRICE that specifically connect the Atmel tools to 3rd party debuggers that do NOT (AFAIK) include any simulation.

[WarSim]

In the microcontroller "software development" world, "JTAG support" most often seems to refer to "using JTAG protocols to access internal registers that control the debug capabilities of the chip", rather than the more traditional "provide ability to set pin states to arbitrary values for system-level debugging."  (huh.  I don't even know whether JTAG on AVR offer pin-setting.  Atmel doesn't seem to document much of their debug capability.)

The other implementation of emulation (I suspect this is the case with JTAG enabled microcontrollers) is to have the microcontroller 'twiddling its thumbs' doing nothing while the host takes full control of all the pins via JTAG under the control of a microcontroller simulator running on the host. This way you can make the 'physical' microcontroller appear to be running the show, where in fact the signal stimulus is done by JTAG.

That seems EXTREMELY unlikey.  The whole point of having on-chip debugging aids is to permit the code to run at full-speed, except when debug functions are explicitly invoked.  There are tools like AVRICE that specifically connect the Atmel tools to 3rd party debuggers that do NOT (AFAIK) include any simulation.

This feature is for debugging the board not the chip.  JTAG pin driving is for simulating chip.