Ben seems to have some interesting hobbies. It would seem that a lightsaber is not the only weapon a Jedi considers worth keeping around. Mounted on Kenobi's wallsare several edged weapons, swords, and what looks like a Kusari gama. So, is this the result of a creative set-dresser, or a legitimate aspect of Kenobi's character to be explored in the prequel trilogy.
The ignition of a lightsaber in the first film was achieved mainly through jump-cuts; the scene would cut from an empty saber to another shot with the saber replaced with a "lit" one. This required shooting different scenes at different times, and so the inevitable continuity error slips in. Here, it is Ben's wall hanging that disappears from shot to shot.
Something to spot: Threepio wakes up from his dormant state as soon as Artoo projects the hologram.
Depending on the camera angle of the scene, the number of knickknacks and their relative position on the table change.
As Luke runs to his speeder to check on his Aunt and Uncle, Artoo has his back turned to the camera. The three rectangles in the center of his back suddenly have color. One of them is gray. Furthermore, when the scene first shows the demolished wreck of the sandcrawler, non-THX copies of the movie have a silent Artoo, while THX copies of the film have Artoo beep.
A fun thing to spot, when Luke returns to the sandcrawler, Obi-wan is sitting on the ground.