I'm in the same boat as Dunster. I don't do pantos or have a computer. I do do a lot of ruler work & free motion. A straight ruler is your top priority. Circles, ovals, melons would be next on the list of most used. Yes, each quilting machine manufacturer has their own rulers or recommendations, but as long as the rulers are 1/4" thick they're usable on any longarm.
As far as learning, Kimmy Brunner's class on Craftsy is a must! She makes it very easy to learn. As far as Youtube, I recommend Jamie Wallen. He's got some awesome techniques with rulers. iquilt.com had classes by Judi Madsen that are good too. And don't forget Angela Walters, although hers are freemotion & not ruler work, but very good.
Looking forward to seeing some of your awesome stuff you create!