My favorite KT88 is the KT88SC is from Penta Labs. This is also a Chinese tube by Shuguang, but is reportedly made to specs of the Genelex 88's. These tubes get rave reveiws over at Audio Asylum and several guys over there swear that these are comparable to their Genelex 88's. I can't speak to that claim, but they are excellent tubes in my system and the best new production tubes I have tried. In my system they better both the EH and SED KT88's. I have placed a link below (pentalabs.com), but if you decide to buy these you should call to make sure you get the the "solid plate" version. If not, you may get the KT88-98 equivalent, which is identified with three holes in the plates and, from what I've read, is considered inferior to the solid plate KT88SC. Also, you can do a search over at the asylum. Theres a lot of talk about this tube.
http://www.pentalaboratories.com/product.asp?dept%5Fid=5020&pf%5Fid=KT88SC+SHUGUANG
http://www.pentalaboratories.com/product.asp?dept%5Fid=5020&pf%5Fid=KT88SC+SHUGUANG