Computer with firewire port, a firewire interface and a condenser mic.

Guess it depends on how many preamps you would need.

If all you're worried about is your voice, you need three things:
1-2 channel mic preamp
1-2 channel A/D(/A)converter (commonly an interface)
one mic that fits your voice

How are you recording into your computer now, or is it all internal?

If you're really serious about your voice, start w/ a great mic preamp, get a converter/interface to match, and then find the right mic for your voice.
Any mic will do, really. Michael Jackson was recorded on an SM7 ($350), Bono of U2 on an SM58 ($100), while others on several thousand $ vintage ribbons and condensers.
You don't necessarily need a $6,000 condenser mic - you need whatever does your voice right. Period.

So focus on the preamp and how you're going to take that fantastic preamp into your computer. I'd allocate around $2,500 for the preamp/interface, and leave the other $1,000 for the mic.
If your mic is an SM58, you have $900 to spend on software. If it is $1,000, you have none - but chances are your interface will come with something quite serviceable.

Also, you have to consider if you plan on recording more than 2 channels at once some time in the future. If so, you'll need an interface that has more than 2 channels and also provides some mic preamps. The starting point for something like this that also meets your A/D/A requirements is an RME Fireface 400/800 ($1,000-$1,700).

Others will have more specific advice on brands/models, but you really need to think about what you'll actually be recording (your voice + others?) and how important your voice recordings are to you.
A great mic deserves a great pre deserves great A/D/A.

Finally, don't fail to consider the role your room plays in making a great vocal recording.
Any info about that would help w/ mic choice, especially.

Hope that helps.

Input:
Mic -> Preamp -> ADC -> Storage Media

Output:
File -> DAC -> monitors / speakers / headphones

It can be relatively cheap, Zoom H2. Where the everything is in a single package. Or a Zoom H4n that lets you plug more advanced mics into it. Beyond that you're looking at an interface. Or a basic soundcard with an external preamp feeding it the mics input. At which point budget comes into play. And how you define High Quality. And purpose of course, voice over or singing? Multi-tracking with pre-existing tracks, or not required? Live and On Stage, or strictly in the studio?

Towards the high end of mics is the Neuman U47 and U87. Tons of preamps in that $1K+ range. And a number of options in converters.

I don't do much voice stuff, but I consider myself on the lower middle class side of recording with a Korg MR-1000 ($1,200 MSRP), Sound Devices MM-1 Preamps ($350 MSRP x2), and a stereo pair of mics Avenson STO-2's ($550 MSRP). Close to $3K at MSRP for that chain. Fortunately I bought most of it used. And not my only options. Next uprade, better mics. Plus all of the accessories to make all that work together. Cables, stands, T-bars, Reflexion filter, Windscreens, pop filters, ....... It adds up quick.

Cascade Elroy mic $299.00
Golden age pre 73 $299.00
MoFET76 1176 compressor $1,149.00
Lynx two converter $999.00
KRK rocket 6in powered monitors $320.00/pair
AKG K240 head phones $99
Cables $150
Stand $40
Auralex Studiofoam Designer Kit acoustic treatment $60.00

All you need for making professional voice recordings for a grand total of $3415.00.