Set #7127 Imperial ATST (Original Version) 2001 and
Set # 7657 ATST - 2007
One of the harder Lego sets to snag now a days for a decent price, the original ATST was one of the smaller sets, originally selling for fewer than twenty dollars this set easily a year ago went for over seventy in the secondary markets. Until the release of the newer ATST which is far bigger and comes with an ATST Pilot and Lego's new sculpt of a laser rifle.
Why does LEGO retire sets? I have no clue, yet it adds to the collectibility to each set and gives collectors more shelf room at retail stores to be able to buy newer sets every year. The First ATST was for a while the only way to get the chicken walker, and it featured a Chewbacca figure, which was either way a really cool trooper to own. Below are photos of each ATST on its own starting with the first released one with chewy followed by the bigger of the two, and then both in a side by side shot for a size comparison, (the smaller of the two could always be used as an Imperial ATPT, the smaller single personal carrier walker for non Star Wars geeks) or just as a trainer for your troops, that's the fun with legos, or any toy for that matter, it's all up to your imagination!