Actually, I have been using the other two components for ages - all my GST and tax etcetera is done in Numbers, and I just save Excel format spreadsheets for my accountant when she wants them. I've never actually used Microsoft's PowerPoint, as I've always found Keynote to be very good. (I run presentations on Apple topics fairly regularly.)
I've also been playing around with iBooks Author: I am considering ditching InDesign to create the MagBytes monthly Apple news and tips newsletters in iBooks Author instead. So if you're one of my hundreds of subscribers, you might see a redesign soon, depending on how it pans out as a PDF maker.
InDesign is the second-to-last Adobe app I'm still using. I used to live and breathe in Photoshop, InDesign (in the magazine trade) and Illustrator, but I hardly touch Illustrator any more. The last thing I ever did in it was creating charts, but Numbers is much easier to use for this and I like the chart styles available. (You will have seen some of these on this blog.)
Photoshop, yes, as I need to get a couple of images ready for mac.nz every day, and for other things. The Save For Web feature is superb, but lately I have discovered a really annoying flaw in that you can't save anything above 72dpi from it. So as good as Photoshop is, I'm looking for an alternative that will let me upload higher-resolution images because lots of people, in the Apple world anyway, view my site on screens with much higher resolutions than 72dpi. Adobe seems unwilling to do anything about it. The closest thing I've found anywhere near Photoshop is Pixelmator, but it doesn't offer an easy Flatten for layers, and the crop tool doesn't work the way I'd like for getting images right for websites, so I have given up on that until these things are fixed.
Apple's Logic is a program I simply love for any audio work. I wish I had time to use it a lot more. It's awesome.
Final Cut Pro X is also great - I don't really work in this field so it's more of doing things to know how it works than serious pursuit, but I do like it a lot.
I do use iPhoto a little, mainly because I teach others how to, but I'm a big fan of Aperture, Apple's pro photo app. It's an extremely good way of looking after my collection of historic family photos and I find the face-tagging a huge help, plus the fact I can add notes to images and search them. The adjustment tools are handy too.
On the genealogy front, I'm a big fan of MacFamily Tree by Synium.
I use Garageband as a quick recorder, almost like an audio notepad, but I'm also a long-time user of Amadeus, which has some great audio tools and which, lately, I've been using as a great way to listen to interviews I need to transcribe for the history books I am working on.
For utilities, I rely mostly on Apple Disc Utility (it's on every Mac, in the Utilities folder in your Applications folder). There is debate on the issue, but I find choosing your hard drive on the left and running Repair Permissions seems to iron out many errors that could otherwise get worse, and that it solves crashing problems and, best of all, seems to speed my Mac up. It's definitely worthwhile to run Repair Permissions after an OS update, by the way. But if Disc Utility can't handle an error, I turn to TechTool Pro 7 and Drive Genius 3.
Apple's Mail for email, for sure. I've never bothered with Outlook - I have run as many as seven email accounts in Mail, all with different rules and signatures etc, and never had a problem, plus it integrates with Calendar, which I also use extensively, and with Contacts. (I do run one Microsoft app - Skype, since Microsoft bought it.)
For news aggregation I recently switched from NetNewsWire to Shrook, but I'm not sure that was such a good idea. I have Omnigraffle Professional for drawing football coaching plans, so that's a seasonal use rather than a full-time one.
Games-wise, I have to admit to a current Borderlands 2 obsession. I only allow myself spells as a reward for work done; I had to take Bioshock Infinite off my hard drive to make room for it. But I just downloaded Tomb Raider Underworld for Mac as it's supposed to be great. I will put off playing this till I've cracked every task in Borderlands, though. But any game would be trumped by anything World War Two-based, for me.
I have a few apps in my right-menu too: Farensius for weather info, SteadyTune for quick guitar tuning, the free Phlo for searching multiple websites, Intego's Washing Machine, Dropbox, and several Apple menus (AirPlay for mirroring to the Apple TV, Time Machine, Wi-fi, Volume, Battery and Keyboard Input Source for changing keyboard layouts between English, Maori and Dutch. You can add these as menus from their panes in System Preferences.
Tell us what you can't live without, Mac-wise, and I'll cover iOS soon.