Proper clothing when on the trail can make a big difference. For information on what I wear in the winter, check out the winter gear page, as this page will primarily deal with summer attire.
I have worn North Face’s Paramount ‘Convertible’ Trail Pants for over two years now, and am quite impressed with them. In middle school, it was uncool to have zip-off pants – now, I can’t love them enough. You see this a lot on trail pants, and its quite a handy feature, as the mountains can often be quite cold at night, and then warm up considerably during the day.
I use these pants for everything from mid to late spring (with a base layer underneath), through the late fall until there is considerable snow. In the summer, I have zipped them off to just shorts, unless I am going through a densely wooded area where I want to avoid thorns/bugs/ticks.
Overall, you essentially get a pair of hiking pants and hiking shorts for the cost of one item. I would recommend picking up a bottle of water-proofer though after the first several washes, as the NorthFace treatment eventually loses its effectiveness.