Re: Upgrades for a Landmark?
Landmark doesn't come with fenders - put fenders on it. I put some composite Planet Bike fenders on mine, and they're great.
You might want to put some better brake pads on it, too. The stock ones wear very quickly. I'm noticing that I have to readjust my brakes very often.
Changing the bars would be a good idea. While these bars are rideable, they force a pretty upright position. The headset on mine won't tighten enough to keep the bars from moving around over bumps, too, and I certainly can't put any weight on them.
Headlight, taillight; these should be obvious.
I haven't replaced the tires or tubes yet, but I have noticed that the tubes ooze pressure over a fairly short time, especially the back one. Make checking your tire pressure a habit. If you're going to replace the tires, don't put knobbies on. Put better street tires on. You shouldn't be offroading with this bike anyway, and knobbies will make for higher rolling resistance.
I wouldn't worry about the pedal chain; you're not going to be using it much anyway.