If you have 2.1 then you must have already rooted. I don't recognize your rom from the info posted. But I highly recommend CyanogenMod 5.0.7. It is a very stable custom ROM, 5.0.8 is probably just as stable, I just haven't upgraded to it. It adds some froyo features. They also have a froyo rom 6.0 RC3, but it is not stable yet.
Check here for more info.
HTC Dream / HTC Magic - CyanogenMod Forum
There is an extra step for us Roger's Magic users, just flashing bcrook's kernel. I am probably no the guy to write a guide for you, but the info is all in the above link if you can figure it out on your own.