OP, that's a purdy one you got there. Congrats!
As for scopes, the general consensus is that 2-7x scopes are the best size for the Marlin 336. This can be a little frustrating if you like to see things in person before you buy, because most retailers tend to stock 3-9x40 and larger scopes, because that's what people seem to think they need.
You can't go wrong, however, with either a Leupold VX-1 or VX-2, or a Redfield Revolution. A Nikon Prostaff is probably not a bad choice, either.