I played a little withthe launchpad. Just enought to get a build environment up (code warrior I think), and a proof of concept project (semi-random frequency beep through a pc speaker at semi-random intervals ).
I was actually surprised how basic the uC is.. 128mB or RAM? That's less than the old PICs.
I also picked up a couple of these, which I think hit a much more interesting price/performance point ( think the uC is similar to the one used in your second dev board):
http://www.st.com/internet/com/TECHNICA ... 277245.pdf
32-bit processor
128KB flash, 8KB RAM,
onboard debugger
lots of hardware peripherals (timers/counters/uarts/DMA etc)
fast
.
.
.
ONLY $12.50!!
It is more involved to get started with, but an interesting step up from the arduino