With the rapid evolution and the prices finally coming down, how long do you think it will be before RAM is no longer needed as a fundamental part of a computer system?

Two years, seven months and twelve days.

RAM, or random access memory could be in the form of SRAM, DRAM, FLASH, CMOS, etc. RAM will change in formfactor in the future, but we will probably not evolve away from it within our lifetimes. There will have to be a pretty drastic change in design. Most everything is loaded off the hard disk and into the RAM and run from there. It is what really runs the PC more than any other component.

RAM could move... onto the CPU, the graphics card, or be build directly on the mother board. However, I don't see us eliminating random access memory in a computer system anytime soon.

I see RAM, getting smaller and smaller. I see it evolving in the next 25 years or so, to the molecular level where a certain type of atom is a good conductor and another type of atom makes a good capacitor. Sending two electrons through for a 1 binary bit, one electron through for a 0 binary bit and none through for a failed connection. Taking the entire world's computer power and placing it in the size of a cell phone, and powering it for a few cents a year.

I see the opposite, with the cloud, less hd space is needed and more ram to load remote code is needed

but I am just guessing

I'm thinking along the lines of what heisenbug was saying. Computer programs are designed around a simple block format.. INPUT > PROCESSING/STORAGE > OUTPUT

A processor will load a computer program into ram, from some other storage media, generally a hard drive, then the processor will execute that code from ram. This is what was taught in an introduction programming class I took just last year. Programming languages use fundamental concepts like "data types". When coding a program with a particular language you must reserve portions of ram to hold the the values you are manipulating and you do that with "data types" For example, an "int" data type, depending on the machine being used, reserves 4 bytes of consecutive ram. A "char" data type, short for "character" reserves 1 byte, or 8 bits, each character corresponding to a character on the ASCII table. A "float" data type is also 4 bytes, but it allows you to use floating point number like 2.7841, where "Int" type would cut off the decimal portion of that same number. I guess my point is that ram will be relevant for quite a while, I believe.