This is really dependent on the vocalist. It's easy to say, "pick up a Neumann or Rode condenser mic", but how do you know how the vocalist will sound in the mic?
If anything, I picked up a couple of inexpensive mic's for vocals and acoustic guitar which I feel sound really good. One of those mics that I have been using more and more is the Apex 210 Ribbon Mic, which is a very fragile mic by comparison to my other mics, but the sound is super sweet. You definitely want to use a pop-shield with this mic. I found that I hardly had to do any real processing with this mic. I haven't tried this one on my guitar just yet, but I just may give it a try just to hear how it sounds.
I also picked up a couple of Tube Condenser mics. I've tried both of these on my guitars and they sound fantastic. One of them is the Apex 470 Pencil Tube, which I find brings out a warm quality from my Ovation 12-string guitar. I may get another one of these to try as drum overheads. The other is is the Apex 460 Wide Diaphragm Tube Condenser which brings out even more character from my acoustic guitars. I haven't yet tried them on vocals as I just got them. But considering how bright my guitars are, these mics definitely warm everything up, IMHO.
These mics go alongside my Apex 415 Wide Diaphragm Condensor. It's warm, but not as warm as a tube condenser. However, it is definitely suitable in certain songs that I do.
If anything, however, these are nothing more than my opinions and very subjective. They work for me and YMMV. What I would recommend is that you rent a few microphones and try them out for a week or so. You will then see which mics work for you and which ones don't.
jord