Azimer's 0.55 - for me the nicest sounding! No crackling and nice, warm bass.
It's not supposed to work that well with 1964, but I don't seem to have any problems (Both Zeldas, SM64, Aidyn Chronicles, Banjo).....but roll on 1964 version 1.0!
Otherwise, Shibo's with internal RSP processing by Azimer 0.40 is also good for me.
I try to avoid using an RSP plugin where possible (slows things down a little).
Specs:
1964 0.99
Latest Plugins (Rice, Azimer etc)
Win XP /SP1
Soundblaster Live!
Geforce 440MX
PIII 1.2GHz
512 MB