PREAMP:
If my answer on the preamps doesn't satisfy you, the gear nerds can give a better answer on the preamp thing as I really couldn't give a damn about them. I've tried out over 40 different pre-amps ranging from SSL consoles to Behringer mixers and I usually just use the one that is available. The modern preamps are pretty good quality and even on the Behringer ADA8000 ones are "usable", but they are a tad noisy, but you won't hear the noise floor in the mix. If you would do a 24-48 track summing, then the preamp choices would start to matter more, but with just a few vocal tracks it's pretty insignificant between similar pre amps and in the mix.
Remember to use a compressor with vocals even when tracking and just get 2-4 different flavours of preamps to choose from. For example use the preamp that comes with your interface, if it has one. For budget choices, the RME Fireface that Joey uses has same preamps as on the RME Quad Mic (~380€ on thomann, 4 channels). The Golden Age Project PRE-73 (~300€ on thomann, 1 channel) is a Neve type preamp and then get a tube pre like Art Tube MP (40€ on thomann, 1 channel). Personally I have 3 different type of preamp: I have the 2 built-in pres on the M-Audio Profire 610, SPL Track One (1ch channel strip meant for vocals with de-esser, comp and eq) and the SM Pro Audio PR8E (8ch preamp).
If you have the cash and you are being serious about recording, go for API A2D (or 3124+) or Universal Audio 610. Can't go wrong with them, and they will last you a lifetime.
MIC:
With the mic, the choices start to matter more and you should have a pretty nice collection of microphones. There are generally 3 microphones that are so called "desert island" microphones: Neumann U87, AKG C414 and Shure SM58. Yes, SM58. I usually A/B compare the microphones so that I put two microphones on top of each other so that the top of the microphones are at the singers mouth height and then choose to use the one that sounds better.
If the singer is really dark sounding (like me for example), use a microphone that is slightly brighter like the U87. If the singer is a bit nasal or the sibilance is really sharp, try the C414 or SM57 as they are slightly darker than the U87.
The 58 and other hand held mics usually also works as the last resort mic too. When the singer is so fucking nervous about the situation, just give him/her a SM58, say "close your eyes and think you are at the Madison Square Garden", press record and hope for the best.
The thing with dynamic mics is that they usually don't get as much sound of the room sound so if your room treatment is less than ideal, getting a mic like AKG C1000, Röde M3 or Shure SM58 might be a good choice, but they usually have more problem with stuff like noise floor,
DISTANCE:
With condenser microphones, you
can actually use distance and the air works as a really good compressor (I'm not kidding). With dynamic mics,
you can't as the voice starts to get really quiet after 3 inches as the coil is really insensitive. The fact that you have to track at close distance from the mic causes proximity effect, so you have to use a pop filter. Personally I prefer metallic pop filters (like
this) over the "panty hose" type cloth pop filters (like
this) as they stop the air flow more efficiently. Or you can get one that has
both
edit: joey was faster than me