Writers need their good tools as much as any other crafts-person. A few of my favorites:
That slow cooker I mentioned a couple of days ago. It’s especially useful in hot weather, and on days when I’m so busy and/or so tired that I have only minimal brain space left for stuff like food and cooking.
A good word processor. And by “good” I mean, “suited to your own preferences and writing habits.” Also, a good word processor for generating text and a good word processor for formatting text are not necessarily the same program.
A good printer. It’s not as necessary as it used to be for a working writer’s printer to be a heavy-duty workhorse capable of printing out 600-pages-and-up inside of 12 hours without breaking down or running out of ink — I think it’s been at least half a dozen books now, maybe more, since we turned in anything in hardcopy — but there are still times when you’ll need a printer, and when you do you’ll want one that doesn’t give up on you in mid-crisis.
A good computer, one with enough hard drive space to store your stuff and enough memory to do the things you need to do.
And all the little things — the red pencils, the index cards, the colored highlighters, the nice fountain pens, and so on — that ease a writer’s heart and make the process of composition easier.
What are your favorite or indispensable tools?
Dr. Doyle's Blog 
I remember the advice we got from Jane Yolen when we got our first reasonable advance: “Buy a dishwasher.”
We did, and Auntie Jane was 100% right.
It was good advice. So was Rita Mae Brown’s advice in Starting from Scratch, where she says that if you’re a freelance writer trying to talk to a banker, bring along your book contracts, because the book contracts speak a language the bank can understand.