I agree with athomas above that a 28L with compression straps is an incredibly versatile pack. You’ll be able to fill it with jackets and thermos for fall/winter hiking, and compress it down for lighter loads in the spring and summer.  ... View more

Your last question really nailed it for my determination on boot height - it depends on what weight I’m carrying.  If I’m below 25lbs (usually ultra-light or short weekend) I’ll opt for lows.  If I’m over 40lbs (usually several days of gear or in winter) I’ll wear full height.  Somewhere in the middle I’ll wear whatever. A second consideration I’d make is whether or not I’m prone to weak joints (aka sprained ankles).  Fortunately, I am not and so I don’t give this much consideration, but I hike with others who are more concerned.  Probably worth some thought. Lastly, season/terrain matters and the more likley you are to be walking through sand or snow you’ll likely want the higher ankle unless you’re wearing gators. ... View more