Ok, so you already have RAM. That sort of changes things.
First off, there is no guarantee that a 3.0C will hit 250 FSB, but seems like a lot of them will. Some folks are even running 250 FSB with low voltages. You could still get a 3.0C and use the 5:4 memory ratio with your old PC3500 RAM.
The 3.4 CPU would be a good match with your current RAM if you insist on using the 1:1 ratio, but there is no guarantee that will do 3.8 gig either.