I use pure C code with the freeware sdcc compiler. it is faster than keil, see interrupt handling, and bugs are fixed very quick.
i have written an I2C code that reads out an AT24C256 32KByte in less than 7 Seconds on an 24MHz device with pure C.
I have used 4 external and 5 internal interrupt sources that do tasks depending on other interrupts with statemachines. very easyly done in c even if you add more states :-)

i do not neet something like borland ide. i use Textpad V4 that does the syntax highlightning and compile the whole stuff with a simple make under cygwin.

Michael Schmitt