RE line-in and mic-in
As to only recording via "line-in" versus "microphone-in", I don't think you can simply plug a microphone into the line in jack--you need to have a pre-amp or other conditioning between a mike and the line-in to get the proper level. Line-in assumes a standard impedance and level (200 mv, I think) which is not normally provided by simply a direct microphone connection, without an intervening mixer/preamp (one of the excellent articles at homerecording.com advises "only line-out to line-in", which is a good rule of thumb).
Dunno if this is applicable here, but thought I should mention it--if you are trying to record with a microphone without a preamp/mixer device you really have no choice but to go "mic-in." And I suppose that may be your point, i.e., "suffer the hiss of an outrageous fortune".