I think you can guess what I'm going to say...

I have Keil - the "Basic" (256K code limit) version: http://www.keil.com/arm/selector.asp
Note that this covers all ARMs - not just Cortex-M3

If you use Keil C51, then you'll know where you are with Keil.

I found setting it up with the uLink a doddle - I just plugged it in, and it just worked.
Similarly with the on-board JTAG probes on the Stellaris boards.
And the on-board JTAG probes on the STM32 Discovery boards.

I used Raisonance about 3 years ago: http://www.mcu-raisonance.com/~arm-fami...sdl47.html
At that time, the only good thing I could say about it was that it was cheap.
Their product was pretty new back then - hopefully it has improved now. I haven't used it since.

I used CodeRed about 3 years ago when they had a free board-locked version for Stellaris with no code or time limits. That worked very well, and was very easy to set up.
At that time, IIRC, the "unlocked" licence was about a third the price of the basic Keil licence.
http://www.code-red-tech.com/red-suite-3.php

Nowadays, they seem to be more closely linked with NXP:
http://www.code-red-tech.com/lpcxpresso.php
http://www.code-red-tech.com/red-suite-3-nxp.php
http://www.code-red-tech.com/lpc1768-d...nt-kit.php

Although CodeSourcery does have a "free" version, last time I looked (a couple of years ago - before the Mentor Graphics acquisition), the cost of getting features (debug, in particular) & support comparable to Keil was comparable to the cost of Keil!

I've not used it but, from what I've seen on the STM32 forum, the free Atollic Lite is very severely crippled.