Last set I got was Muaka and Kane Ra from eBay at half price. Came with everything but the infected Hau.( or haus?) Which I regret, because I made the combiner and lost various parts to the void that eats Lego parts.
Although for this Christmas I might get Takua and Pewku, along with Gahlok, Pahrak, Kohrak Kal, and Nuvok Va.
My last set was turaga vakama.
Stars Takanuva in 2012.
Toa Inikia Kongu several months ago.
My last set was Stars Gresh. I told my self I would probably never buy a Lego set after that. But Lego handled the new toa so well that now Iām convinced.
THE GAME HAS CHANGED
Hmmā¦last set from the official line when Bionicle was still alive was Stars Gresh and Tahu. And I biult Tahu last, so that makes him my last official Bionicle set. But as for the most recent one with online purchase or some other stuff, Makuta Teridax.
Last Bionicle set was probably one of the Stars, last I remember is ScorpioXV_1 though.
Last CBS set was the Chima sets.
Last Lego set was the Guardians of the Galaxy sets.
Update: The latest BIONICLE I bought was at 7:23 Mountain Time today. It is Makutanuva with all parts and pieces. =D
The last set I got? Iām proud to say, Hewkii Mahri. The canon-arm was a cool deviation from the norm, as were the maskās little quirks. 
I loved the Mahriās customizable Kanohi.
stars Tahu
And I never got another stars set past that
The last Bonkle set I got was Pahrak Va, for my birthday this year
Heās quite and I finally have another Krana (my first krana was lost :()
I once got a stars Skrall, then returned it to the store due to fear of cracking parts (my only regret is not having a Kopaka mata sword in black any more).
I actually once returned a 2008 Kopaka after some joints cracked first build.
My last BIONICLE set was Piraka STARS. I have not bothered buying more sets since then, but I plan on collecting all of the 2006 sets.
piraka starsā¦psh its isnt a piraka stupid lego
no seriously for some reason lego named him piraka
he is nektaan
Last week I got Karzahni, Maxilos, and a set lot which had thok, panrahk, tahnok, tahu nuva(had him already), gali nuva(same deal), reidak(yup), balta(same) and a broken down sidorak(also had him already).
last set I got was the Stars, but they all snapped and broke ;_;
I got all of them at once and decided, āHey! I should try the combiner set!ā worst idea ever, and almost all of the joints broke when I was converting them back to their normal form. Now I mostly just have their masks and weapons, and thats it 
But black Kopaka sword FTW!
Tell me about it. cough tanma cough
Ps. My stars are ok btw.
My last Bionicle set was either Stars Nektann or Stars Rahkshi, probably the former.
But wait!
After Bionicle ended, I bought Pohatu Mata at a garage sale. Iām not sure if that counts, though, as I already had a Pohatu Mata.
One of the Stars set, it was either Takanuva or Nektann. Actually, I think I got them at the same time.
The last set
I got was tahu mata wich I got on ebay a few days ago.