It's a toss up between my Gillette New, Tech or Slim. It just depends on the mood I am in when I decide to shave. Although I have really been digging my New since it's Open Comb October
I always come back to my Merkur Vision 2000. I've tried just about every DE made but the Vision is one that is just too nice a shaving machine to put away for very long. I have to force myself to NOT use it, otherwise I would not use any of my other razors (yea it is that nice)
My Slim is my favorite, but the iKon OC runs a close second with the FatBoy third. My other runners up are iKon SB baseplae, Jagger De86, and Merkur 37c.