iPAD, KINDLE, KOBO… HELP!

K so I’ve been thinking long and hard about switching from paperback books… my beloved pulpy musty books, some dog eared, some with coffee stains, some with sun damage, some with tear stains, and all with memories of my feelings while reading them…. TO… switching to an e-reader of some sort.  Hubby thinks I should get an iPad as I will probably get one sooner than later and I don’t want to be lugging an iPhone, iPad, and ereader of some sort…. can I please have suggestions if you use a kindle, a kobo, an iPad or whatever else is out there… Also wondering, what is easiest to get books, can you buy kobo books and use them on other devices, as with kindle’s etc.  if I have an iPad would I have to always purchase through iTunes?  I’m not very swift with downloading things that aren’t spywear and other crap.
PLEASE HELP ME DECIDE!