My Hiker (it was made by Pur at the time) has been going strong eight years.
In addition to the standard pump filters there are other options:
Chemical treatment (for me it takes too long, doesn't filter out crud, and can alter the taste)
Gravity filter: Such as the Katadyn Base Camp filter.
Bottle based filters: Such as the ExStream (some of which also kill viruses)
Ceramic filters: Which get at smaller contaminants than filters like the Pur, but weigh more. Actually First Need gets at smaller particles (even viruses) and isn't ceramic as far as I know, but does weigh more than the Hiker.
The Steri Pen: I saw one in action and it seemed pretty cool. It worked fast, was about 7 ounces with Lithium batteries and even kills viruses. It uses UV-C light to sterilize water. I also saw someone in a shelter curse his SteriPen and come close to smashing it.