These are all already listed over here, with the link to the Spotify playlist:

http://drownedinsound.com/news/4143220-spotify-playlist--drowned-in-sounds-songs-of-the-year-so-far

But here's what DiS writers said about their choices.

(Number one to be revealed this afternoon.)

45 Holy Other - Feel Something
Another ender from the EP of the year so far - Manchester's Holy Other may seem shrouded in a darkened hue, but the triumphant smashes of electronic percussion on this track prove he has more eyes to the sky than to the ground."
William Grant

44 Florrie - Begging
I am not the sort of person who particularly likes to draw attention to herself while out in public, but if you come to Norwich there is a good chance I will be listening to this while I am At Large. What I will probably do is not sing it as you approach me on the pavement. But once you are behind me and I cannot see your face anymore I will RWD to the chorus and sing ‘Begging Me’ out loud. I’m kind of carefree.
Wendy Roby

43 KATY B featuring MS DYNAMITE - Lights On.
Features Ms Dynamite" would have most people running for cover. Not us, as not only does 'Lights On' relaunch the one-time Mercury Music prize winner as a credible artist, it also highlights why Ms Brien is the best popstar Blighty has produced in years.
Dominic Gourlay

42 Young Magic – You With Air
Do try to get someone to snog you while this is playing very loud. I hesitate to used the word ‘swirly’ because ‘swirly’ has been given a bad rep by the chillwavers, but ‘You With Air’ is swirly. But not in the sort of way that makes you imagine a hippie girl dancing in an ‘ethnic’ skirt made of twigs.
Wendy Roby

41 Eddie Vedder - 'Sleepless Nights'
In releasing a solo ukulele record, Vedder managed to express both a contentment with growing older as well as a bullheaded punk rock audacity. Certain tracks worked better than others, but here Eddie’s rich voice, Glen Hansard’s backing vocals and the tiny Hawaiian guitar’s tinkling strings sound perfectly in sync and achieve a somewhat timeless quality.
J.R. Moores

40 Fear of Men - spirit house (cassette mix)
Not out till August 2011 on Italian Beach Babes and as yet underhyped. But there it is an eerily catchy guitar song about liars and dreaming with pretty backing vocals.
Alex Hegazy

39 The Antlers - Putting The Dog To Sleep
A glorious slow-dance to end a near perfect response to the acclaimed
Hospice', Silberman and co. show that their romantic hearts are beating just as fast as ever with the closer of 'Burst Apart'." William Grant

38 Friendly Fires – Live Those Days
It was a close run between this and ‘Hurting’ for my fave song of the year so far. But I’ll go for this: a ridiculously massive tune drenched in pool-side rave euphoria that makes me want to drink cocktails and copy Ed’s hip wiggling thing.
Dannii Leivers

37 Thurston Moore - 'Benediction'
Like the Judas Dylan in reverse, Thurston Moore bravely emasculated himself of his signature electric guitar skree, roped in Beck to produce, and somehow managed to cook up one of the most sublime acoustic/string records since Nick Drake popped his clogs. Is there anything this man can’t do? J.R. Moores

36 The Mountain Goats - Age of Kings (From All Eternals Deck)
Because it reminds me of the Princess Bride and makes me want to drop everything i'm doing and write epic fantasy novels, posthaste.
Eli Lee