Two of the year's biggest blockbusters went head-to-head against one another as they debuted on DVD and Blu-ray last week, with the result paralleling their box-office performance. Night at the Museum Battle of the Smithsonian, which earned $177.2 million domestically, debuted in first place on the Nielsen VideoScan First Alert DVD sales chart, while Terminator Salvation, which grossed $125.3 million, came in second. The two films also placed first and second respectively on the rental charts, according to Home Media magazine, which tracks home video DVD rentals.On the Blu-ray charts, however, the two films reversed positions. In Blu-ray sales, the trade publication observed, Terminator outsold Museum by a margin of nearly 3-1. The movie pushed Disney's Up to third place in its fourth week on the charts.