Lpc2000

Hi,

there have been many ports to support the LPC2000 family already.
Ashling, Hitech, IAR, Keil, Rowley just to name some of them (in
alphabetical order). Also the ARM RealView and GHS support the family. 
In my personal opinion, the most important consideration is what you
used so far rather than the difference in features. If you are a
migrating 51-customer and you used IAR or Keil and you were satisfied,
the logical choice is to stay with them. Same is true if you are
migrating from PIC and used Hitech or from MSP430 / AVR and used IAR,
stay with them if you like the IDE. Another consideration is what kind
of debugger / emulator you want to use. If Ashling is your first
choice, you might also want to use their compiler port (single source
supply). If Nohau is your favorite, they work closely with Hitech and
IAR. If Hitex is your favorite, the closest partner is Keil. If you
use a standard wiggler, Rowley seems to work very reliably.

The long story short, there are too many combinations to recommend an
IDE that suits everyone. 

Some statements have already been made:
Rowley works nicely with Olimex tools
Keil has the best simulator (helpful for more than 1 breakpoint in
flash memory)
In general dedicated compiler such as GHS, ARM, IAR and the new kid on
the block Hitech have a little better code-density than a GNU-based
compiler. Whether that is important for you, you decide. 

Summary: there are a lot of mature tools on the market and you might
want to get an evaluation version, compile some code and compare the
results based on your own code. You will also see the difference in
look and feel between the tools you will evaluate. A lot of the like /
dislike is personal taste.

Hope I did not offend any of our tool partners while still providing
some useful information ;-)

Regards, Robert