I usually wait for Last Chance, a sale on specific sets or discounted shipping to pick up sets. I did get the Bee Hive set for Christmas and I am really enjoying it.
As far as new sets go, I just ordered the Armstrong LP set as it hit Last Chance. I'd like to get the Mingus as soon as it gets back in stock. Other than that - I'll have to see what the next sale brings. I think they usually run something around Father's Day in June. Would like to grab the Savoy as well.