High Level is the standard and we use it exclusively at Power Marketing. Our own White Labeled version is called Mako Automation, but the foundation is High Level.

Webhosting Provider - Hostinger (I used Bluehost for years but they just got worse and worse every year and now they are just not useable. The problems are endless: email deliverability, horrible customer support, horrible UI on cPanel, and just slow hosting, etc.). I have switched over to Hostinger and I wish I would have done it years ago!
Files Sharing - DropBox (if you don't have this already you need to get it right away—it's FREE)

Software for Design and Photo Editing

Adobe Creative Suite (Photoshop, InDesign, Illustrator)
Lightroom (photo organization and editing)
Portrait Professional (to rapidly edit portraits)

Video Related Software

Screenflow (Screen Capture)
Apple Final Cut (Video Editing)
MPEG Streamclip (for video encoding)
Presentation Prompter (Teleprompter)
Handbrake (for ripping DVDs)

Audio Related Software

SonicFire Pro (for royalty free soundtracks)
Audio HiJack (for capturing audio that plays on my computer)
Sound Studio (ultra simplistic yet powerful audio editor and exporter)
Pro Tools (audio editing—industry standard, but we also use Logic)