Usually the general opinion is that a veiled chameleon or a panther chameleon are the easiest to care for. Veileds eat a LOT, are easily obtained and inexpensive, and are very tempermental. Panthers are good eaters as well, but not nearly as voracious as veileds, are fairly expensive, and usually have a more mild temperment (by mild i mean not AS aggressive, but can still be aggressive).
A small cage is better for a smaller chameleon because it is easier to monitor their food intake, their poop, etc. It is also easier for the chameleon to find their food in a smaller enclosure. Make sure that the cage is heavily planted so that the chameleon can hide so that it feels secure.
I don't handle my chameleons unless absolutely necessary. It does indeed stress them out and it is unnecessary. Some people will tell you that their chameleons like the interaction, will walk right up to them, aren't aggressive, etc. and this may be the case but in my time keeping chameleons, I haven't had one that didn't show some sort of stress when being handled. And yes, enough stress can eventually weaken and kill your chameleon.. even if indirectly.
You will also need supplements.. one that is pure calcium with NO D3 or phosphorus, one that is calcium WITH D3 and no phosphorus and a vitamin supplement.
You will also need food to gutload your crickets with. Dark greens, carrots, sweet potato, grains all work well. No spinach or broccoli.
You will need a digital thermometer with a probe or a temperature gun to take accurate basking and ambient temps. A hygrometer (humidity gauge) is also needed.