Neon Tetra's can be pretty fickle fish, especially in a new tank, Cardinal Tetras are slightly more hardy - and much better looking - but can be expensive. That's not to say you shouldn't get them, I would just recommend getting them last once your tank is well established. With a 55 you can always have a separate school of 10 or so fish in addition to your tetras. Maybe something hardier to start out with like Harlequin Rasbora (very underrated fish imo) or White Clouds until your tank is well established.
Also, with a planted tank it would be a good idea to get some Otocinclus catfish. These little guys are awesome algae eaters (of course you need to supplement their diet with veggies as well) They're also small and stay out of sight when they're not clinging to the glass. These are great utility fish. I have both Cories and Oto's in my tank. The Cories scour the bottom for food that sinks during feedings and the otos keep my plants, glass, driftwood, and even filter intake tube nice and clean.