Tim, I have tried-
Audioquest, Kimber, Lat, Rega (yes, they make cables), MIT, Tributeries, and a few others I can't remember. I have built my own from Belden coax, Cat 5, magnet wire, Genesis cable, Some very old (1920's) solid twisted three conductor cloth insulated hard drawn copper wire, and my current favorite- silver plated copper solid conductor wire, with 5kv rated Teflon insulation. I do not use or recommend any of the lower priced Monster cables, since they really don't sound very good to me. I believe the capacitance is too high in the lower cost Monsters and the top end rolls off slightly. (this will be very system dependent, since roll off is affected by equipment impedances) However, I get very good results from Studio link 500 and 1000, proving to me, that when someone claims all Monster Cable is crap, they haven't tried all Monster Cables.
I am really reluctant to spend more money on interconnects at this point, though.
(edit) I should add, that so far my exsperience is that cables made with similer materials, and similer geometries sound very much identical.