A little list, many of which you may have heard before. I'm not really a hip-hop expert. When I DO 'dig' its for reviewing purposes mainly and I rarely find stuff that I think is really good.
Curren$y + Alchemist - Covert Coup (favourite album/EP of last year, probably, listen to it more than anything else from 2011)
Ka - Grief Pedigree (took me a little while to get into but is really excellent - tight, sparse monotone New York thug rap - beats are often brilliant and Ka is compelling in an introverted, emotionless way)
Meek Mill - Dreamchasers
Danny Brown - XXX (a masterpiece... probably only listen to 'Covert Coup' a LOT more than this because XXX is harder work, longer, and demands to be listened to front-to-back)
Juicy J - Rubba Band Bizness 2 ('Who Da Neighbours' and a lot of other Lex Luger produced tunes like it but slightly inferior to it... great)
Boldy James - Trapper's Alley: Pros And Cons (very long but full of really good tracks, mostly erring more towards sample-heavy, Dilla-Esque soulful beats.)
Chief Keef - Back From The Dead (pure savagery, most effectively violent/zombie-like mixtape since ''Flockaveli''?)
Lil B - Six Kiss
Kendrick Lamar - Overly Dedicated (this is from 2010, it's great if you haven't heard it though - 'Section 80' is supposedly very good from last year (?) but I haven't listened to it yet, honestly)
Rick Ross - Rich Forever (better than 'God Forgives...')
Gunplay - Bogota Rich: The Prequel (LOVE THIS - Gunplay is one of the best rappers around (sadly probably not for much longer if he goes to jail) and this mixtape is short and sweet... he just kills every other rapper on this).
Main Attrakionz - Best Of Compilation - all the Main Attrakionz stuff I love, or most of it.
Wiz Kalifah - Kush and Orange Juice - This is going back to 2010 too but this was a really good tape. Better than anything I've heard by him since, that's for sure, though has moments of cheesiness.
ALSO RANS
Gucci Mane - Trap Back (now I'm getting to hear 2007 era Gucci I don't really rate the newer tapes as highly as I did, but they're still pretty good and worth a listen.)
ASAP Rocky - Live Love ASAP (essential, though I don't listen to it much anymore)
Big KRIT - Return of 4Eva
Starlito - Mental Warfare (I wanted to include a Starlito mixape because he's a really great rapper but his mixtapes - the ones I've heard, anyway - tend to suffer from mediocre production. But he's definitely worth checking out. This and 'Ultimate Warrior' and 'Post Traumatic Stress Syndrome'.)
Waka Flocka Flame - Lebron Flocka James 3 (A lot of Flocka tapes are interchangeable to a degree - big Southside and Lex beats, Flocka screaming and groaning over the top. This features many a hellacious fist-fight starting banger. 'Call Me Inky' and 'Gold and Platinum' for example.)
Wooh Da Kid - Black Out (Brick Squad tape, very moody and nasty... 'Danger', 'Body Bags', some of my favourite tunes of 2010)
Ice Burgandy - P.I.R.U. (again, I can't honestly say I listened to this all but there are some definite 2012 highlights on this 'PMBB' primarily)
GrandeMarshall - 800 (reviewed this recently for The Wire. It's basically influenced by ASAP Rocky and Kendrick Lamar, I would say. Low-key, 'cloudy' beats, very good.)
Ab Soul - Control System
Shady Blaze - The Grind, Hustle and Talent
Schoolboy Q - Habits and Contradictions
Young Jeezy - Thug Motivation 3
Max B - Vigilante Season
DG Yola - Mr Broke Da Knob
French Montana - Coke Boys 2 (Harry Fraud beats)
Action Bronson - Blue Chips
Roc Marciano - Marcberg
TKO Capone - Duck Season vol 1 (I'm in the process of reviewing this and I'm hesitant to praise it because I feel I might just be going mad but I basically LOVE this. Generic as fuck trap production and TKO Capone - sometime Riff-Raff collaborator - mutters/mumbles in a Gucci Mane/Lil B style - all the time coming with groan-worthy punchlines and a liberal amount of ignorant nastiness... for 40 tracks. Very entertaining and funny.)