I use the Katahdyn Hiker for solo trips. Cheap and simple with no problems. I use a coffee filter around the filter and it never clogs.

I also have a Katahdyn Base camp for when I am hiking with two other friends. Jeez, I love the heck out of that thing! Scoop up a gallon or two of water, tie it to a tree, put the outlet hose in a bladder and walk away to pitch tent or fish. Clean water without any pumping. Uses same filter as the Hiker, too!

I wish they made a smaller bladder for the base camp, I would use it for solo. Seriously, just scoop up water and hang it. Nice after a long day in the sun.