We recently talked to another family who had also just moved to New Zealand from the US, and we were on the subject of appliances. Apparently they had purchased several plug converter units with transformers, and intended to run various appliances through the transformer. Even their toaster! We have one of those 220V-to-110V transformers with a maximum power output of about 50 watts. A toaster is going to draw about 750 watts. That's pretty much going to cause the transformer to bite it.
Those transformer units aren't cheap (at least USD$40 from REI), so they'll be out one transformer and one toaster (having no way to power it). On the other hand, we bought a brand new toaster here for about NZD$6.
Actually I just noticed that some transformer units have a high-wattage setting so you can run devices like a hair dryer. That would work for a toaster too. Still, USD$40, or NZD$6 (about USD$3.70)? Which would you choose? We got a new TV that understands both NTSC and PAL, and a new DVD player that came with instructions on how to set it to region-free mode. Trying to bring our existing appliances with us would have been really expensive and pretty disappointing overall.
We went to a garage sale the other day and saw a cheap microwave oven. However, the power plug appeared to be a European style plug, and it was sitting in what appeared to be its original shipping box with Korean writing on it. We passed on that one.