Programmers and programming environment are another thing. No offence to MikroE ARM compiler, but I've never heard of them outside of PIC and I have no idea what programmers they support other than their own and what chips they support other than STM and Stellaris. I don't know how much support you will get hobby wise. If you are not making commercial products, I would suggest a non-commercial license to Rowley Crossworks ($150). It's just a GCC compiler at this time, but they support a lot JTAG programmers and chips and there is a lot of support. It's just real easy to use.
I'm using and Olimex USB-ARM-JTAG with a Crossworks adapter for SWD, but I have a J-Link clone here (I got it from DX.com) I'm looking at trying and I have the STM32 F0 Discovery board that comes with the ST-Link 2 JTAG programmer on it. I'm going to try that with the LPC chips to see if it works. Not certain why it wouldn't. There are no ARM chips from different manufacturers that are pin compatible that I know of. They are all very different.
I'm not a fan of the MikroE style board where they try to put everything on a single board, but I understand that some might be. If you want to step into it first, the cheap Devel boards with JTAG debuggers built in are:
STM32 F0 Discovery - The F0 is the cortex-m0 board. Crossworks supports the ST-Link 2 programmer.
LPCXPRESSO LPC1114 - again, the M0 board. Crossworks does not support the LPCXpresso JTAG debugger that comes on this board. I think it's only supported by Code Red.
EK-LM4F120XL from TI - Just heard about this yesterday. This is a cortex-M4F device (M3 with DSP extensions). Not certain what the programmer is here or if it's supported by anything other than TI's crippleware programming environment. It's only $5, though. Same price as a MSP430 launchpad. You can get it here:
http://estore.ti.com/Stellaris-LaunchPad.aspx EDIT: The JTAG programmer is the Stellaris ICDI which Crossworks supports.
MicroBuilder is a good place for LPC support.
**broken link removed**