I have to put my vote in for the Rickenbacker. Years ago, I was playing in a rock band. I had a Gibson ES-335 and a Telecaster. I traded the Tele for a Rickenbacker 6-string and my singing improved measurably! (So did my guitar playing) For me, the Rick hangs just at the right angle so I was no longer fighting the guitar to play it. The concentration no longer required for that I was able to put into my singing, improving that! The Gibson has since been sold, and I am keeping that Rick for the rest of my life. It's now the only electric in my collection. My $.02 worth.

jeffp