What budget has your friend got ? click here e-buyer have some good budget systems available at the moment.
They're all future proof to the extent that memory and VGA card can be upgraded. But the base machines are not going to support the new areas of PC tech like PCI express so are not infinitely up datable.
Not sure I agree with your bare bones comments, in most cases bare bones refers to a case, usually supplied with a MOBO and power supply and nothing else. No CPU, memory, hard drive, operating system or peripherals.