Here, from our friends at BlendTec, a gps put to the best use I can imagine.
I'm not a big fan of gps for sea kayaking. I think their use is dorky and their utility over-rated. So very few of us actually paddle far enough offshore or in areas remote enough to require one. Mostly they get used as mapping units to track trips and post routes online for others to see. So in that application they're more a scrapbook than anything else.
They're a gadget mostly owned and used by middle-aged guys who can't paddle very well. ;-)
Nonetheless, search Amazon if you really think you need one.