Bag seed strains. I haven't tried too many different designer seeds yet, but I am looking.
I came across an awesome strain from some bag seed about 11 years ago and I haven't come across anything like it since. I sure wish I would have taken cuttings from it. I won't make that mistake ever again.
Otherwise, so far my favorite designer seed is the TGA Querkel, it is not the most potent but it is one of the most enjoyable I have had.
Either way I will continue my search for a comparable to that old bag seed strain I had 11 years ago.