What I get the most from this quote is to Live Life to the Fullest, because you never know when today may be the last day. The last day for what you ask? As sad as it is to say, it may be your last day, the last time you see a loved one, the last time to talk to them.... so make it worth while and something you will hold as a dear memory.
I have had several friends who have lost loved ones unexpectedly in the last few months. They were young, and should still be here, but they are not, so remember, what you do today holds a dear memory, whether for you or someone that is close to you.
And as for dreaming and planning, we all need that in our lives, it gives us hope and something to look forward to. For years I dreamed of owning my own business, and never having to work for someone else, and I never really thought of it as more than just that, a dream. But years later, an opportunity arose, and I took advantage of it, and now I have a very nice small business. I won't get rich, most likely, although I do still dream :), but it helps us to live a comfortable life, and we really don't want for anything.
I would love to hear some of your dreams or plans, so make sure to leave me some comments letting me know what yours are.