David said "I've had some luck with the Osprey Talon 22. Probably the most feature rich, yet lightweight daypack available."
^ that's the exact route I went as well. I've used the Marmot Kompressor (which is very similar to a lot of the other very light offerings) and while it is indeed light, I find myself needing to carry more gear than probably what those really light packs are meant to. It's a great pack to stick in your backpack if your planning a lot of side trips during your backpacking trip, but for long (my day hikes tend to be on the long side), single day day hike they just didn't offer the capacity or the comfort of the Talon. I plan on using the 22 for snowshoeing this year, appears it should handle those duties pretty well too.