Hello Gec, welcome to the board! I can't tell you much about computers for recording, as my studio is based on a stand alone hard drive recorder, but I will tell you what I have learned about mics and preamps. First, every mic needs a preamp. Mixers have preamps in them, but they're not usually very good ones. You have to build the signal chain from the beginning, rather than the end.
You will get better recordings from a great mic and preamp into a cheap soundcard than from a lousy mic and pre into a great system. The problem with vocal mics is that they are like a pair of pants. One size does *not* fit all, and there is no vocal mic so good that it will not sound like hell on some singer. Change songs or keys, and you may find a different mic will work better. Also, some singers sound great on a cheap mic, through the right preamp. All you can do is buy proven good mics and pres, so if they don't work for you, they're easier to sell. And never miss an opportunity to try out a friend's mic, just for the experience. Make friends who own microphones!
Preamps are critical, and good ones are the basis of almost every great recording. Here are a few to check out:
Dirt Cheap- M Audio Audiobuddy, M Audio DMP-3, Studio Projects VTB-1
Better (more money) FMR Audio RNP, Grace Design 101
High end (excellent- price of good used car) anything by Avalon, Great River, Pendulum, Davisound, DW Fearn. Check preamps at Mercenary Audio on line for some sticker shock. For your purposes, I'd consider starting at the middle level, about $500.
Microphones- Basically, there are dynamic mics and condenser mics. Ribbon mics are a special type of dynamic with a metal ribbon instead of a diaphragm. Tube (or valve) mics are condensers that contain a vacuum tube to add selective distortion, often called "warmth". Before you are done, you will want a good dynamic, a good FET (no tube) condenser, and a good tube mic. Add a ribbon later. Some mics worth considering:
Cheap Dynamics-
Shure SM58, AKG D880
Higher end Dynamics- Shure SM7B, Sennheiser MD421 and MD441. Any of these are wonderful mics.
Cheap Condensers- Marshall MXL V67B, Studio Projects B-1 and C-1, Oktava MK319,
Rode NT-1a
Middle Level Condensers- Rode NT1000 and NT-2, B.L.U.E Baby Bottle and Dragonfly, Studio Projects C-3, Neumann TLM103, AKG C414TL-II
Middle level tube mics- Rode NTK, Studio Projects T-3
Vocal Condensers to die for- (and break the bank)- Neumann U87, B.L.U.E. Kiwi and Cactus, Lawson L47, Brauner any model, AKG C12, Rode Classic II.
That should lay out some basic options in preamps from $80 to $5000+ and mics in about the same range. For a kickass middle level combo, I would probably opt for B.L.U.E. Dragonfly and Grace 101, then add Rode NTK for a basic tube mic and Shure SM7B for a great dynamic. Best of luck to you. Stick with it. This recording thing can be very testosterone driven, and recording definitely could use a woman's touch. There are a few here, especially Riley357 and Shakee Tee.-Richie
PS- there are dozens of preamps and mics I have not mentioned that work just fine, But I can confidently recommend all of what I listed as being good stuff in its price range.