I've been implementing firmware based on Coreboot on a number of AMD- and Intel-based boards for my employer, Arastra.
If you plan to do any serious firmware hacking, a flash programmer is an indispensible tool. It's the only way to program a flash chip on a brand-new board with no existing firmware.
The key to a good programmer is good software that's kept up-to-date with the programming algorithms and parameters for a variety of flash chips.
EETools TopMax flash/EEPROM programmer is the one I use. After fighting a losing battle with a cheap no-name flash programmer for a few weeks, I managed to find the TopMax on a dusty shelf at my local Fry's Electronics (much to the surprise of the Fry's employee who told me they hadn't stocked programmers for years).
EETools software supports zillions of different chips and posts updates regularly on their web site. It's reasonably well desgined, stable, and Just Works[tm].
The only major downside is that the EETools software is Windows-only. This seems to be par for the course among professional-grade programmers; last time I checked, Linux support was available only for the more do-it-yourself "Willem" programmers. I just hook up the programmer to an old laptop running Windows.