It was hard to find a Best of '09 list that didn't include the xx -- not bad for a debut release from a group of British barely-legals. The eponymous LP covers a lot of ground in just 40 minutes, mixing in elements of post-punk, dreamy pop, and R&B.

More than the genre shifts, the record is driven by the beautiful boy/girl vocal interchange between Romy Madley Croft and Oliver Sim. The two always sound sultry and almost-sad without coming across as pretentious or overly dramatic.

Most impressive is the band's restraint. The pair always has exactly the right amount of backing -- guitar lines that simple and unimposing, beats that guide the tracks without forcing them, and subtle keys that fill in any gaps. And though the record is slow and dreamy, it never feels sleepy. This debut will be a hard act for the band to follow.