I have two small kids so I go to Ruby's at least twice a month. My favorite burger used to be called the beach burger, but now it's called the super burger. It is a grilled patty with melted swiss and avocados on grilled parmesan cheese bread. Delicious! But VERY fattening so I don't indulge often. Ruby's recently introduced sliders as well (kobe beef, pulled pork or....I can't remember the third.) I like the kobe beef slider. There are three and are served with grilled onions on King's Hawaiian rolls. The meat is perfectly spiced and the sweetness of the roll balances it out nicely.
That being said, the simple cheeseburger is also quite good. I guess it just depends on your mood and your appetite. Oh and the shakes/malts are great as well- but again I don't indulge often.
So I went and here is a quick write-up.
I had the simple cheeseburger with cheddar and garlic fries. The burger was very satisfying and the fries addictive. I'd feel comfortable going back and doing some more exploring, especially with the blues burger. I'm also interested in the cajun fries.
My girlfriend had the mushroom swiss burger with chili fries. I liked hers a bit more then mine, and the fries were good as well, but mine were better. She ended up eating the majority of mine.
We split the oreo shake which was great. The waitress recommended coming back in the fall for their pumpkin shakes.