i've done 3 or 4 g1's now. Pretty simple. Usually go with the cyanogen rom. Seems to be the most stable.
With the cyanogen rom, and setcpu overclocking it, the ones i played with actually became phones i wouldn't mind having for a backup or just to play with.
I've rooted and flashed G1's, mytouchs, my evo and an htc hero.
i'm hoping someone will let me get my hands on their samsung epic, intercept, or moment. haven't had the chance to see the difference in those for the rooting and flashing process yet.