As time goes on I’ve come to inhabit an almost exclusively-Apple universe, though, as the list below indicates, I do use other software.
Mac Users should find just about everything you need either bundled on your Mac when it arrives or in the latest incarnation of iLife (iPhoto, iMovie and Garage Band) and iWork (Pages, Numbers and Keynote) though iLife no longer includes iWeb, so =I’m doing my website stuff with RapidWeaver.
Still, sitting in my Dock at the moment, I have:
Word Processing:
Drafting: TextEdit
Prepublication: Pages
Publication: Pages, RapidWeaver and iWeb
I draft in TextEdit and add the formatting later. With the first draft done, it’s a copy and paste into Pages for spellchecking and proofreading. Save in Pages, add formatting if appropriate (the Save is a backup precaution) and then it’s another copy and paste into whichever environment will be used to publish the content. That’ll be a combination of my Blogger app (see below) and RapidWeaver (website content). That might seem a bit over the top, but it gives me two or three chances to review and double check before publication.
Spreadsheet:
Numbers (also have the iPad app to sync data, though I’m not sure it’s a good idea. Security and all that)
Database:
Bento (iPad app syncs all data across, very handy)
Presentations:
iPhoto, Keynote
More...