for those who are primarily actors, but may do other stuff too:
headshot - is it in color? Is it less than 2 years old? do you have headshots for stage? commercial? business/industrial?
resume - is it up-to-date? proofread? do you have versions for stage? on-camera? different resumes for other slashes (teaching, directing, etc)
website - is it up-to-date? does it have your headshot and resume in easy to download formats? your contact info? your current projects?
reel - is it around 1 minute long? do you have different reels for your different types of on-camera work (commercial, industrial, film, comedy, dramatic, etc.)? are they labeled appropriately? on your website?
voiceover demo - do you have demos for the diff voiceover categories you work in (commercial, industrial, character, promo)? on your website?
postcard - does it have your image (or logo if you're voiceover only)? your web URL?
business card - your name? your contact info? an image or logo? a tagline?
tagline - do you have a short, accurate, on-brand description of yourself? do you use it with your online profiles?
elevator pitch - can you describe who you are and what you do in less than 1 minute and also convey your professionalism and personality
monologues - do you have at least four awesome monologues of contrasting tones and styles ready to do right now if I said 'go'?
professional bio - do you have bios for each of your slashes that are up-to-date, proofread, and on-brand?
references - 3 of them, with phone number, email and mailing address, typed and ready if I asked for them?
press clippings - one page of them, give or take, where critics from major sources have said complimentary things about you?
additional professional photos - of you in productions or at work, that could go in a press packet if asked
modeling portfolio photos - if this is one of your slashes, do you have a portfolio of images? is it on your website?
professional online profiles - are you listed in the appropriate places for your industry (imdb, theatre bay area, casting search sites)? are these up-to-date? include the appropriate media (reel or photo or voiceover demo)
contact list - are you keeping contact info of people who've hired you, that you've auditioned for, etc?
What I'm learning is that the items on this list are actually never done, just okay 'for now' and require regular updating, maintenance, revamping, etc. So work on one, get it to where you like it and then move on to the next.
What did I leave off this list that you have on yours?