I teach this for a living, so I could cover most of the possibilities,if you wish.
This is my home set-up.
An 8 bus analogue mixer connects to an M Audio Delta 1010 interface.
Sixteen analogue channels on the mixer can be routed to the 8 audio inputs into the computer (PC), running Pro Tools 7.4 M Powered.
At College we use a DigiDesign 002, giving us 8 inputs to a G5 Mac, or in the Analogue studio, a 24 track Spirit Desk runs direct outs into an Alesis HD24 - a dedicated hard disk recorder.
All of these come close to professional standards.
Many students are happy to record 2 tracks at a time onto their Mac laptops. This can be adequate as far as sound quality is concerned.
They are divided about 50/50 between Digidesign M Boxes into Pro Tools, and Edirol interfaces into Logic 8.
In my opinion,if you are bringing other people in, you should not be using free software, nor can you use "Good" and "Behringer" in the same phrase. I have tried Audacity, but I'm not happy with the sound quality of the plug-ins- but you get nothing for nothing!
Reaper is just too quirky if you are used to the pro software, both programs seem to be based on the idea of low-fi home MP3 production for amusement.
If you have good mics, I'd recommend getting some higher-end kit.
Check out the reviews in Sound on Sound
Sound on Sound Magazine
Cheers
Dave