So I want to experience a bit with with ARM
Both of these boards lack an onboard debugging interface.
They have a JTAG connector, but to use it you'd also need to buy a USB-JTAG adapter.

You could program the processors with ISP, but for that you'll also have to make a special cable, use additional software for programming and you won't have debugging possibilities (you'll only be able to upload the compiled program).

If you want to just try something out without having anything particular in mind, a good solution would be the STM32VLDISCOVERY. It is cheap an has an on-board ST-Link interface that can be later used to debug your own devices with an STM32 processor. It simply connects to a PC via USB.

If you have an understanding of what type of devices you'll be making, you should figure out what interfaces, peripherals you'll need and pick an evaluation kit accordingly.
Or maybe it'll be easier to breadboard the additional elements.
Olimex makes many boards for many processors.

To begin doing something you'll also need a compiler / development environment.
You need to chose between a GCC solution or one of the commercial compilers.

GCC is a bit of a pain to setup, but is unrestricted and free. If you decide to go this route and you're on windows, have a look at a combination of CooCox (for the development environment) and yagarto.

If you decide to go for the commercial compilers, you could start with the size-resricted versions of Keil or IAR. ARM bought Keil some time ago, so maybe that would be the "best" compiler to chose, since it's made by the same company that makes the cores.