A few years ago I bought 100 feet of housing off of ebay for like $5. It was pretty cheap, it tended to cut very uncleanly (cheap spiral metal?) and the housing would crack.
I picked up some SRAM Flak Jacket Cable Housing from Speedgoat back in February and have just recently installed it. It is a neat system. It has ferrules that extend past the end of the cable stop, where a sheath goes over it and creates a fairly closed system.
Also it does not hurt that it goes so well with the color scheme on the mudhoney.
The front derailleur uses a little rubber boot on the end to keep the crud out.
The exposed cable run on the rear seat stay is encased in this cover, I think it works well.
The brake cables, which are Avid bb7 Disc and Ultegra STI levers run silky smooth in the housing as well.
I have had these on the crosser for just two weeks but they have been out on a couple of muddy spring rides and have not been adversely affected at all. I even but them on my Turner, where the solid cable housing run from the Avid lever to the BB7 rear is indistinguishable from hydraulic.
This comes in the package:
I have had these on my cross and mountain bike for a while now and they are really nice. They have kept the crud out during the wet spring and they are still shifting smooth.
I will put these on again.
-Joe