I'll do a top 50 list in December
but just a couple that spring to mind:
Kate Nash - Do-Wah-Doo (which is really weird because I HATE her.)
Scissor Sisters - Skin Tight
Mini Viva - I Wish (technically Nov. 09 but meh)
M.I.A. - XXXO
Sleigh Bells - Rill Rill
Brandon Flowers - Crossfire
Arcade Fire - Month Of May / We Used to Wait / Half Light I
Kings of Leon - Radioactive
The Naked and Famous - Young Blood
Kelis - Scream / Acapella (the latter I had last autumn but it was released this year)