Depends. The 2.1 stock baseband (c_01.3e.03p) works the best for me. Pete Alfonso has a C_01.43.01P all in one update (available through rom manager or [BASEBAND] C_01.43.01P (No Prerequisite Required!) - Droid Forum - Verizon Droid & the Motorola Droid Forum ) that has worked for a lot of folks, but some (myself included) needed to roll back because reception got worse. You can try the update out and if it doesn't work you can always roll back.
You can roll back by downloading http://mydroidfiles.com/downloads/basebandupdate.zip (which should be the c_01.3e.03p baseband) and choosing the "install zip from sdcard" option in clockworkmod. The update.zip approach might work as well, after renaming the file and saving it in the top level of your sdcard, but I haven't tested this approach.