I hear that. Another thing that I don't really have a grasp on is how to get the pre-amps into the computer. Interfaces aside, I see A/D converters, PCI cards, pre-amps, all kinds of connections and shit going on. How is all that getting into the computer? I'm just taking a wild guess, but the pre-amp connects to the converter and the converter connects to the sound card?
They're all different forms of the same thing.
Most computers, for example, have a built in "sound card" which includes a very basic mic pre amp, an A to D, and a D to A feeding the speakers/headphone socket. The quality of these built in devices is very low (they cost pennies to make) but they ARE the basic chain.
For more serious recording and mixing, it's more common to use a specialist audio interface/sound card. These used to be almost all PCI cards with some kind of break out box or fan of cables, but, in the last 10 years or so, the most common form of these have become external boxes connecting to the computer with USB or Firewire. Whether PCI, Firewire or USB all these do basically the same job as the built in card, just with hugely better quality.
The most common audio interfaces contain the whole package: microphone pre amp(s), Line Level inputs, A to D converter and a D to A converter. The better ones also have extra controls to allow monitoring without feeding via the computer with the latency that entails. However, they don't all have all the bits and pieces since not everybody needs everything.
Some have just Line Level inputs and the A to D, D to A parts, assuming you'll use an external pre amp or mixer for example. Others have mainly/all digital inputs (things like ADAT, AES etc.) which are then adapted into a computer input via PCI, Firewire or USB. FYI, that's what I use--a digital mixer with ADAT outputs and a box that adapts the ADAT into Firewire.
Anyway, don't worry too much if people use the phrase Sound Card or Audio Interface. They're pretty much the same thing. Similarly, PCI, Firewire or USB all work to get into the computer (though PCI and Firewire are getting scarce these days).
What you DO have to do though is read through the specs very carefully. Almost all Audio Interfaces will claim to have "14 inputs" or whatever--but, on reading you'll find that the ten include only two mic pre amps, two line sockets which are shared with the XLRs for the mics so you can't use both at once, a stereo digital input on RCA/Phono and an ADAT input (requiring an external box with mic pres and ADAT out. You just need to make sure you have the inputs that you need.
My advice is still to just buy a good, all-in-one interface known to have good pre amps and let it go at that. However, if you're dead set on having an extra pre amp, make sure your interface has line level inputs NOT shared with the built in mic preamps, otherwise you end up going through the interface mic pres anyway, just padded down for level.