For decorative carving I would go with palm handles, I think. Beyond that, anything you can keep sharp. I did my first rifle with a 1 mm chisel made from an exacto blade, a pocket knife, and a couple of small chisels and gouges from a set that cost $10 for 12 chisels - nothing but dowels with a cheap blade stuck on the end (they were a gift, and I didn't have the money to buy better. I don't like them much, but I have to admit that they work pretty well if they were sharp.) The end result isn't too bad...
Having said all that, get the best you can afford. Buy some slipstones, too. The Scary Sharp method works well, but you need something to get the inside of your gouges.
edited to add: I haven't tried their chisels or gouges, but I do have a Flexcut drawknife that I love. Their stropping compound is superb, and well worth the money.