I'm always searching for cool apps to make my life easier/better/cooler. Lately, I've come across quite a few and have had a little cash to actually buy some that are worthwhile. I thought I'd compile a list here to share, to get suggestions, and just so I had them all written down.
Also: If you have any suggestions/alternatives/other categories you want to see, please let me know!
Gradient - $4.99 - Create CSS3 gradients without hassle
Pencil - Free - Wireframe a website with ease
Coda 2 - $75 - By far the best code editor for web development I have ever used. Just read through the site. You'll understand.
Transmit - $34 - The fanciest FTP client you can use and it's well worth the price. One thing: Finder mounted SSH connections. The end.
Prompt - $7.99 - Need a terminal to connect to a server? Yeah you do.
iTunes - Free - Obviously...
Vox - Free - Super non-intrusive music app that just works. Import the music you want to listen to and just listen.
CarTunes - $4.99 - By far the best app for listening to music while you're driving; everything is gesture based so you really don't have to finagle with your iPhone/iPod while driving.
8tracks - Free - Playlists you can stream on the go. What's not to like?
PowerTimer - Free - Power Hour. 'Nuff said.
gMusic - $1.99 - Play music from your Google Play account aka probably your whole iTunes library.
DropTunes - $0.99 - Stream music from your Dropbox account, if you're into that sort of stuff.
Evernote - Free - Take notes/pictures/video/audio all in one. Tagging/categorizing/etc. So awesome.
Evernote - Free - Take notes/pictures/video/audio but from your phone!
NameMangler - $9.99 - For when you need to batch-rename files. I do this so often manually (aka renaming 100+ files one-by-one) that this was a must have. Pricey, but worth every penny.
BetterSnapTool - $1.99 - Snap windows all around your Mac's screen. Similar to the functionality in Windows 7, but a bit more powerful.
CheatSheet - Free - See what key combinations you're using on your computer. Kind of handy when you accidentally press something and your computer wigs out.
DockDrop - Free - Drop files on this dock icon and have it immediately upload any sized file to a personal server/WebDav/SCP/Flickr(pictures only). Super simple. Super awesome.
ScreenGrab - Free but no longer available (I have the .prefPane if you're interested) - Automatically upload screenshots to a personal server when you press Cmd+Shift+3 or Cmd+Shift+4 and place the URL on your clipboard.
Alfred - Free - Quick Launch just about anything, do math, and much more all from a simple key command.
AppTrap - Free - Asks to delete associated files when uninstalling an application (dragging the app to the trash)
Growl - Notifications for hundreds of applications.
Prowl - $2.99 - Basically, you can use this to get alerts for just about anything on your phone. It's pretty damn handy. I use it with wordpress to send updates when someone submits a post to DestroyTheCyb.org!
Slice - Free - Get notifications on any kind of delivery that provides updates (Amazon, UPS, etc.). You can even set it up to auto read from your inbox and pull UPS/FedEx/etc. from your incoming e-mails.
Gas Cubby - $2.99 - Track your MPG/usage/etc. for your car. Tune-ups too!
Dayta - Free - Stats for anything you want. Requires you to input almost everything about what you want to track, but exporting and setup is pretty seamless.
WolframAlpha - $1.99 - Your favorite "solve everything" website is now on your phone. What more is there to say?