I've seen that wiremold could be an interesting way to carry the wires
throughout the house, but it seems to be expensive when you need a lot, and it
doesn't look nice. But never minding the look, has anyone here had any
experience with this?

I've used Wiremold many times in older houses, and as for looks, it is a
subjective thing. In older houses, with reasonable placement of the conduit it
tends to look OK, I think. Newer houses, though are better served with
trenching out the stud crossings and installing guards over the wires before
patching the drywall.
Check out the Wiremold web site (www.wiremold.com) for more info or call
1-800-621-0049 to request a Buyers Guide. FWIW, the stuff is easy to work with,
and is even available at some box stores with a decent selection of bits and
pieces.
HTH

Joe