Like bckpk2rev I am a backpacker primarily and a bike tourer second, and I have to say go with a small, utlralight one person tent. I have used them all, bivys, ponchos, tarps, hammocks, and unless you really enjoy sleeping in a hammock, a tent cannot be beat, especially for when you need to change clothes, get stuck in because of bad weather, etc. Also, a hennesey hammock or Clark Jungle Hammock (what I have used alot) can be totally insane in a bad storm. They swing like crazy in really windy places, and in prolonged rain almost always water gets in somehow.
Many of the one person tents out now are suprisingly light, and spacious for a solo tent.