Bobby:
It is very very hard in todays world with the features of on-board flash memory that can be programmed via ISP to recommend that you go with a processor that requires external programmable memory. Since you said you are looking for CAN bus capability as well then you should look closely at the Cygnal's C8051F040 -> C8051F043 series parts. These have on-board CAN, 64K bytes of FLASH and operate at 25MHz. Note that 25 MHz on the Cygnal part is far higher performance than 40 MHz on a Dallas 390. The Cygnal operates with a direct instruction cycle rate of 25 MHz. The DS80C390 divides its 40 MHz by four to derive an instruction cycle rate of 10 MHz. Here is where to see the C8051F04x Family Data Sheet.

The Cygnal parts also offer an on-board JTAG interface (accessable from PC COMM port through a Cygnal supplied adapter) that supports the FLASH programming and a full set of hardware based debug support including breakpoints, watch points and single stepping. With these parts there is no need to acquire some sort of other emulator to support program debug.

Michael Karas