I am just starting out too, but the one great suggestion my DH had was instead of a Wilton box--a tackle box. You know one for fishing. We went to look at the wilton box and he said-Honey, a tackle box would have more compartments and better storage. Man was he right! I already had most of my supplies (Christmas, b-day, anniversary, wish list) so the tackle box idea was great.
I am the envy of my Wilton classes because I can find everything so quickly in its own little space instead of digging through the one compartment of the Wilton box. Most of my icing I take to class will fit in it too.