We do gift cards- usually $25 each, to Target. When DS was 1 and 2 I gave gifts to everyone, aides, bus drivers, anyone. It got a little ridiculous because I was giving things to people I've never met or heard from, so recently I've pared down to just the main teacher and the therapists he sees the most often.
Btw if you do choose to give to everyone, I really don't think you have to get nuts. The first year I did a little local gourmet food item (about $5 per). Another year all Starbucks cards for $5 or $10.