I like both of these songs, as minimalist and repetitive as as they are… but is it just me, or are they kind of the same even though they’re different? It’s probably just me.
I feel the same way about the beginnings of these songs, too:
SIDE NOTE: I like the acid flashback feeling of seeing the old CD cases in the Letterman clip.
monkeyBLOG monkeyDO 
Okay, after a couple of days beyond ‘musing,’ I think the Tegan & Sara and Metric songs are only similar in that they contain minimal music, repetive lyrical segments, a lilting voice, and are catchy as hell. They DO NOT sound at all alike.
I stand by my second two songs, tho…