Borrowed from Rich Leonardi:
Things that I haven't done that I hope to do:
(1) Design and have built our own house, on a decent sized piece of land, with no HOA in sight.
(2) Read the Iliad in Greek (though this becomes diminishingly likely as each year results in more forgotten Greek vocabulary and grammar).
(3) Have a book published. (Or course, this requires actively getting back to writing...)
(4) Finish reading A Dance to the Music of Time. (After five years, I've read 9.5 out of the 12 novels.)
(5) Go on vacation with just my wife.
Things that I haven't done that I can do without:
(1) Own a big screen TV.
(2) Read something by Ayn Rand.
(3) Upgrade to Windows Vista.
(4) Keep a dog.
(5) Have a playstation, xbox, etc. under my roof.