My tradition has been to prepare taxes within Apple's Numbers app, uploading the template I use here. The spreadsheet started with automatically updating tables for the main Federal 1040, and has gradually grown to include some helpers for Schedule A, Schedule C and Schedule E.

I've hit a new low for uploading late this year, sorry; I didn't finish up my own return until yesterday afternoon. So if you still need this, I hope you filed an extension ;-)

Download: f1040-2014 Numbers template

Posts for previous years with perhaps a bit more info: 2013 2012 2011 [skipped 2010] 2009 2008