OP -- the reason you're getting such varied advice is because you haven't communicated what basic approach you want to take. perhaps you don't know. here's an overview:
live 2-track take
1. set up 2 mics
2. have everyone play at once
3. record to stereo recorder
live 2-track take w/ live mixdown
1. set up multiple mics
2. have everyone play at once
3. mix mics to stereo with mixer
4. record to stereo recorder
live multitrack take
1. set up multiple mics
2. have everyone play at once
3. track each mic to its own track in the computer
4. mix down to stereo later
live multitrack take with overdubs
1. set up multiple mics
2. have everyone play at once
3. track each mic to its own track in the computer
4. record additional parts later, each to its own track in the computer
5. mix down to stereo later
overdub session
1. set up mics for 1 or more players
2. record them, tracking each mic to its own track in the computer. perhaps they're playing to previously rendered backing tracks, like something done in Reason.
3. add parts one or more at a time, tracking each mic to its own track in the computer
4. mix down to stereo later
each approach is viable. each can result in excellent recordings. some approaches are more complicated, requiring different kinds of gear and engineering approaches.
the approach you use is influenced by how the band plays together, what kinds of parts they want to play, what equipment is available, what recording rooms are available.
in any case, you need mics. you need at least a stereo recorder, perhaps a full DAW with a multitrack a/d converter. you'll need to be able to hear what you're doing, whether that be headphones or a full monitoring setup in a control room.
the final result is a combination of the skills of the players, the skills of the engineer, the viability of the approach chosen, and the quality of the gear. roughly in that order.
iow, the presence/absence of GarageBand won't kill you. not having any mics, or not knowing what to do with them, will kill you.
